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timestamp[us]date 1999-12-11 03:00:00
2025-04-28 00:58:08
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|---|---|---|---|---|---|---|---|---|---|---|---|---|
A004101 | Number of partitions of n of the form a_1*b_1^2 + a_2*b_2^2 + ...; number of semisimple rings with p^n elements for any prime p. | [
"1",
"1",
"2",
"3",
"6",
"8",
"13",
"18",
"29",
"40",
"58",
"79",
"115",
"154",
"213",
"284",
"391",
"514",
"690",
"900",
"1197",
"1549",
"2025",
"2600",
"3377",
"4306",
"5523",
"7000",
"8922",
"11235",
"14196",
"17777",
"22336",
"27825",
"34720",
"43037",
"53446",
"65942",
"81423",
"100033",
"122991",
"150481",
"184149",
"224449",
"273614",
"332291"
] | [
"nonn",
"nice",
"easy"
] | 50 | 0 | 3 | [
"A004101",
"A006171",
"A038538",
"A280451",
"A280661",
"A280662"
] | [
"M0753"
] | N. J. A. Sloane | 2024-03-06T04:52:43 | oeisdata/seq/A004/A004101.seq | 191271ebf2efb7c212531423535269b1 |
A004102 | Number of signed graphs with n nodes. Also number of 2-multigraphs on n nodes. | [
"1",
"1",
"3",
"10",
"66",
"792",
"25506",
"2302938",
"591901884",
"420784762014",
"819833163057369",
"4382639993148435207",
"64588133532185722290294",
"2638572375815762804156666529",
"300400208094064113266621946833097",
"95776892467035669509813163910815022152"
] | [
"nonn",
"nice",
"easy"
] | 61 | 0 | 3 | [
"A004102",
"A053465",
"A063841"
] | [
"M2874"
] | N. J. A. Sloane | 2024-07-09T19:14:19 | oeisdata/seq/A004/A004102.seq | 687fde9bff0be89ba10f8c32a2821d74 |
A004103 | Number of nets on n unlabeled nodes. | [
"1",
"2",
"9",
"56",
"705",
"19548",
"1419237",
"278474976",
"148192635483",
"213558945249402",
"836556995284293897",
"8962975658381123937708",
"264404516190234685662666051",
"21610417954162750247842392794292",
"4921335335427778307286708119839406529",
"3138313838161414849743136458064895837170596"
] | [
"nonn"
] | 34 | 0 | 2 | [
"A000666",
"A004102",
"A004103",
"A004107"
] | [
"M1942"
] | N. J. A. Sloane | 2024-07-09T20:54:42 | oeisdata/seq/A004/A004103.seq | 7fa54e22dbc2dceb277eb015de72f3a4 |
A004104 | Number of self-dual signed graphs with n nodes. Also number of self-complementary 2-multigraphs on n nodes. | [
"1",
"1",
"2",
"6",
"20",
"86",
"662",
"8120",
"171526",
"5909259",
"348089533",
"33883250874",
"5476590066777",
"1490141905609371",
"666003784522738152",
"509204473666338077658",
"636051958071749028811326",
"1375164117171886868027357906",
"4844133410739656724629165903483",
"29777568550007746192195431057341474"
] | [
"nonn",
"nice"
] | 52 | 1 | 3 | [
"A004102",
"A004104",
"A052111",
"A052112",
"A052113"
] | [
"M1649"
] | N. J. A. Sloane | 2024-07-09T15:47:53 | oeisdata/seq/A004/A004104.seq | 5859e8b2fe84e00a6698d921c9982e4e |
A004105 | Number of point-self-dual nets with 2n nodes. Also number of directed 2-multigraphs with loops on n nodes. | [
"1",
"3",
"45",
"3411",
"1809459",
"7071729867",
"208517974495911",
"47481903377454219975",
"85161307642554753639601848",
"1221965550839348597865127102714827",
"142024245093355901785105779901319683262778",
"135056692539998733060710198802224149631056479068139"
] | [
"easy",
"nonn"
] | 55 | 0 | 2 | [
"A000595",
"A001374",
"A004105",
"A053467",
"A053516"
] | [
"M3153"
] | N. J. A. Sloane | 2024-07-10T15:03:07 | oeisdata/seq/A004/A004105.seq | a9dfe2478afc4e7d3a7ca3abc1d3e731 |
A004106 | Number of line-self-dual nets (or edge-self-dual nets) with n nodes. | [
"1",
"2",
"3",
"8",
"29",
"148",
"1043",
"11984",
"229027",
"6997682",
"366204347",
"30394774084",
"4363985982959",
"994090870519508",
"393850452332173999",
"249278602955869472540",
"275042591834324901085904",
"488860279973733024992540668",
"1514493725905920009795681408275"
] | [
"nonn"
] | 39 | 0 | 2 | [
"A004103",
"A004104",
"A004105",
"A004106",
"A004107",
"A320490"
] | [
"M0889"
] | N. J. A. Sloane | 2024-07-10T15:02:59 | oeisdata/seq/A004/A004106.seq | e22034d651152e3cb55d798e53c03d44 |
A004107 | Number of self-dual nets with 2n nodes. | [
"1",
"1",
"9",
"165",
"24651",
"29522961",
"286646256675",
"21717897090413481",
"12980536689318626076840",
"62082697145168772833294318409",
"2405195296608025717214293025492960466",
"762399078635131851885116768114137369439908725"
] | [
"nonn"
] | 33 | 0 | 3 | [
"A004103",
"A004104",
"A004105",
"A004106",
"A004107"
] | [
"M4663"
] | N. J. A. Sloane | 2024-07-09T16:31:58 | oeisdata/seq/A004/A004107.seq | c2360e8d2c56e4cc1fcb71275ed9048a |
A004108 | Number of n-node unlabeled connected graphs without endpoints. | [
"1",
"1",
"0",
"1",
"3",
"11",
"61",
"507",
"7442",
"197772",
"9808209",
"902884343",
"153723152913",
"48443147912137",
"28363697921914475",
"30996525982586676021",
"63502034385272108655525",
"244852545421597419740767106",
"1783161611489937453151313949442",
"24603891216883233547700609793901996"
] | [
"nonn"
] | 77 | 0 | 5 | [
"A004108",
"A004110",
"A006024",
"A059166",
"A059167",
"A092430",
"A261919",
"A342556",
"A342557",
"A349402"
] | [
"M2910"
] | N. J. A. Sloane | 2025-02-17T12:20:40 | oeisdata/seq/A004/A004108.seq | 57304644bfc719bb19ac73baa3cfeef4 |
A004109 | Number of connected trivalent (or cubic) labeled graphs with 2n nodes. | [
"1",
"0",
"1",
"70",
"19320",
"11166120",
"11543439600",
"19491385914000",
"50233275604512000",
"187663723374359232000",
"975937986889287117696000",
"6838461558851342749449120000",
"62856853767402275979616458240000",
"741099150663748252073618880960000000",
"10997077750618335243742188527076864000000"
] | [
"nonn",
"nice"
] | 36 | 0 | 4 | [
"A002829",
"A002851",
"A004109",
"A324163"
] | [
"M5345"
] | N. J. A. Sloane | 2024-08-28T12:41:51 | oeisdata/seq/A004/A004109.seq | 09eeb01666dca37809c908d279e637e6 |
A004110 | Number of n-node unlabeled graphs without endpoints (i.e., no nodes of degree 1). | [
"1",
"1",
"1",
"2",
"5",
"16",
"78",
"588",
"8047",
"205914",
"10014882",
"912908876",
"154636289460",
"48597794716736",
"28412296651708628",
"31024938435794151088",
"63533059372622888758054",
"244916078509480823407040988",
"1783406527599529094009748567708",
"24605674623474428415849066062642456"
] | [
"nonn"
] | 85 | 0 | 4 | [
"A000088",
"A004108",
"A004110",
"A006024",
"A059166",
"A059167",
"A123551",
"A129584",
"A261919"
] | [
"M1504"
] | N. J. A. Sloane | 2024-09-14T13:26:42 | oeisdata/seq/A004/A004110.seq | 46b7e9172c449ba8dd968c4940f2bae4 |
A004111 | Number of rooted identity trees with n nodes (rooted trees whose automorphism group is the identity group). | [
"0",
"1",
"1",
"1",
"2",
"3",
"6",
"12",
"25",
"52",
"113",
"247",
"548",
"1226",
"2770",
"6299",
"14426",
"33209",
"76851",
"178618",
"416848",
"976296",
"2294224",
"5407384",
"12780394",
"30283120",
"71924647",
"171196956",
"408310668",
"975662480",
"2335443077",
"5599508648",
"13446130438",
"32334837886",
"77863375126",
"187737500013",
"453203435319",
"1095295264857",
"2649957419351"
] | [
"nonn",
"easy",
"nice",
"eigen"
] | 118 | 0 | 5 | [
"A000009",
"A000081",
"A000220",
"A004111",
"A027750",
"A035056",
"A196118",
"A196154",
"A196161",
"A227819",
"A246169",
"A255517",
"A316074",
"A316101",
"A318757"
] | [
"M0796"
] | N. J. A. Sloane | 2024-07-06T09:23:36 | oeisdata/seq/A004/A004111.seq | af3ff2c9d64756174540aeb67f5bdaa7 |
A004112 | Numbers k where |cos(k)| (or |cosec(k)| or |cot(k)|) decreases monotonically to 0; also |tan(k)|, |sec(k)|, |sin(k)| increases. | [
"0",
"1",
"2",
"5",
"8",
"11",
"344",
"699",
"1054",
"1409",
"1764",
"2119",
"2474",
"2829",
"3184",
"3539",
"3894",
"4249",
"4604",
"4959",
"5314",
"5669",
"6024",
"6379",
"6734",
"7089",
"7444",
"7799",
"8154",
"8509",
"8864",
"9219",
"9574",
"9929",
"10284",
"10639",
"10994",
"11349",
"11704",
"12059",
"12414",
"12769",
"13124",
"13479",
"13834"
] | [
"nonn",
"nice"
] | 51 | 1 | 3 | [
"A002485",
"A004112",
"A024814",
"A046947",
"A046956"
] | null | Clark Kimberling | 2025-02-16T08:32:28 | oeisdata/seq/A004/A004112.seq | 9455089d18c85d88b2bf31cf8cbb5823 |
A004113 | Number of rooted trees with n nodes and 2-colored non-leaf nodes. | [
"1",
"2",
"6",
"18",
"60",
"204",
"734",
"2694",
"10162",
"38982",
"151920",
"599244",
"2389028",
"9608668",
"38945230",
"158904230",
"652178206",
"2690598570",
"11151718166",
"46412717826",
"193891596436",
"812748036380",
"3417407089470",
"14410094628558",
"60920843101858",
"258169745573158",
"1096494947168142"
] | [
"nonn",
"eigen"
] | 38 | 1 | 2 | [
"A004113",
"A004114",
"A052316",
"A052317"
] | [
"M1629"
] | N. J. A. Sloane | 2021-12-26T20:50:55 | oeisdata/seq/A004/A004113.seq | 3a4492db61b747732156be3737abe3ba |
A004114 | Number of trees with n nodes and 2-colored internal (non-leaf) nodes. | [
"1",
"1",
"1",
"2",
"5",
"12",
"33",
"98",
"305",
"1002",
"3424",
"12016",
"43230",
"158516",
"590621",
"2230450",
"8521967",
"32889238",
"128064009",
"502590642",
"1986357307",
"7900377892",
"31602819524",
"127076645038",
"513419837168",
"2083414420394",
"8488377206876",
"34712566540014",
"142443837953632"
] | [
"nonn",
"nice",
"easy"
] | 29 | 0 | 4 | [
"A004113",
"A004114",
"A052316",
"A052317"
] | [
"M1422"
] | N. J. A. Sloane | 2021-12-26T20:51:19 | oeisdata/seq/A004/A004114.seq | 3c97664f2cb8616764293de66ed74236 |
A004115 | Number of unlabeled rooted nonseparable graphs with n nodes. | [
"0",
"1",
"1",
"4",
"22",
"178",
"2278",
"46380",
"1578060",
"92765486",
"9676866173",
"1821391854302",
"625710416245358",
"395761853562201960",
"464128290507379386872",
"1015085639712281997464676",
"4160440039279630394986003604",
"32088534920274236421098827156776"
] | [
"nonn",
"nice"
] | 29 | 1 | 4 | [
"A002218",
"A004115",
"A007145",
"A013922"
] | [
"M3592"
] | N. J. A. Sloane | 2021-11-07T15:28:17 | oeisdata/seq/A004/A004115.seq | f0b5b95aca6e33b5ca17edf3391d0b0a |
A004116 | a(n) = floor((n^2 + 6n - 3)/4). | [
"1",
"3",
"6",
"9",
"13",
"17",
"22",
"27",
"33",
"39",
"46",
"53",
"61",
"69",
"78",
"87",
"97",
"107",
"118",
"129",
"141",
"153",
"166",
"179",
"193",
"207",
"222",
"237",
"253",
"269",
"286",
"303",
"321",
"339",
"358",
"377",
"397",
"417",
"438",
"459"
] | [
"nonn",
"easy"
] | 74 | 1 | 2 | null | [
"M2524"
] | N. J. A. Sloane | 2022-08-13T06:23:33 | oeisdata/seq/A004/A004116.seq | 3e245cc5ec28b1f05e79e3adadec87ec |
A004117 | Numerators of expansion of (1-x)^(-1/3). | [
"1",
"1",
"2",
"14",
"35",
"91",
"728",
"1976",
"5434",
"135850",
"380380",
"1071980",
"9111830",
"25933670",
"74096200",
"637227320",
"1832028545",
"5280552865",
"137294374490",
"397431084050",
"1152550143745",
"10043651252635",
"29217894553120",
"85112997176480"
] | [
"nonn"
] | 34 | 0 | 3 | [
"A004117",
"A004128",
"A004987",
"A007559",
"A034689",
"A047657",
"A053101",
"A054861",
"A072888"
] | null | N. J. A. Sloane | 2025-01-19T14:36:09 | oeisdata/seq/A004/A004117.seq | 4c224a741e1465a56caab8bb49151567 |
A004118 | Maximal excess of a Hadamard matrix of order 4n. | [
"0",
"8",
"20",
"36",
"64",
"80",
"112",
"140",
"172",
"216",
"244",
"280",
"324",
"364",
"408"
] | [
"nonn",
"hard",
"more",
"nice"
] | 15 | 0 | 2 | [
"A004118",
"A019442"
] | [
"M4489"
] | N. J. A. Sloane | 2022-01-31T01:27:26 | oeisdata/seq/A004/A004118.seq | be9b22db34646d05fee9b8515bfbb7df |
A004119 | a(0) = 1; thereafter a(n) = 3*2^(n-1) + 1. | [
"1",
"4",
"7",
"13",
"25",
"49",
"97",
"193",
"385",
"769",
"1537",
"3073",
"6145",
"12289",
"24577",
"49153",
"98305",
"196609",
"393217",
"786433",
"1572865",
"3145729",
"6291457",
"12582913",
"25165825",
"50331649",
"100663297",
"201326593",
"402653185",
"805306369",
"1610612737",
"3221225473",
"6442450945",
"12884901889"
] | [
"nonn",
"easy"
] | 87 | 0 | 2 | [
"A000051",
"A002253",
"A004119",
"A008776",
"A039687",
"A049775",
"A049988",
"A181565"
] | [
"M3308"
] | N. J. A. Sloane, R. K. Guy | 2023-07-13T09:19:50 | oeisdata/seq/A004/A004119.seq | e62b1d8f682bc433c50918174e4e5f41 |
A004120 | Expansion of (1 + x - x^5) / (1 - x)^3. | [
"1",
"4",
"9",
"16",
"25",
"35",
"46",
"58",
"71",
"85",
"100",
"116",
"133",
"151",
"170",
"190",
"211",
"233",
"256",
"280",
"305",
"331",
"358",
"386",
"415",
"445",
"476",
"508",
"541",
"575",
"610",
"646",
"683",
"721",
"760",
"800",
"841",
"883",
"926",
"970",
"1015",
"1061",
"1108",
"1156",
"1205"
] | [
"nonn",
"easy"
] | 56 | 0 | 2 | null | [
"M3354"
] | N. J. A. Sloane | 2025-02-01T23:19:32 | oeisdata/seq/A004/A004120.seq | d5fe3cacb8a4ddc125798297ed8ac0b0 |
A004121 | Generalized weak orders on n points. | [
"2",
"16",
"208",
"3968",
"109568",
"4793344",
"410662912",
"82657083392",
"38274970222592",
"37590755515826176",
"75458309991776124928",
"305873605165090925969408",
"2491832958314452159507202048",
"40704585435508852018947014262784"
] | [
"nonn",
"nice",
"easy"
] | 26 | 1 | 1 | [
"A000670",
"A004121",
"A004122",
"A004123"
] | [
"M2095"
] | N. J. A. Sloane | 2022-01-31T01:27:54 | oeisdata/seq/A004/A004121.seq | b1990d97f42ee83b3dd1fb308bbf42b0 |
A004122 | Generalized weak orders on n points. | [
"2",
"13",
"123",
"1546",
"24283",
"457699",
"10064848",
"252945467",
"7151532895",
"224661610888",
"7763387794649",
"292659248485051",
"11951855446598278",
"525645673381008537",
"24769319755329986599",
"1244984053628241578058",
"66487872534167725541751"
] | [
"nonn",
"nice",
"easy"
] | 20 | 1 | 1 | [
"A000670",
"A004121",
"A004122",
"A004123"
] | [
"M2064"
] | N. J. A. Sloane | 2022-01-31T01:28:11 | oeisdata/seq/A004/A004122.seq | 6df66b68afed5822fb54c616932c1c02 |
A004123 | Number of generalized weak orders on n points. | [
"1",
"2",
"10",
"74",
"730",
"9002",
"133210",
"2299754",
"45375130",
"1007179562",
"24840104410",
"673895590634",
"19944372341530",
"639455369290922",
"22079273878443610",
"816812844197444714",
"32232133532123179930",
"1351401783010933015082"
] | [
"nonn",
"nice",
"easy"
] | 96 | 1 | 2 | [
"A000165",
"A000670",
"A004121",
"A004122",
"A004123",
"A032033",
"A050351",
"A094416"
] | [
"M1975"
] | N. J. A. Sloane | 2024-05-03T01:16:45 | oeisdata/seq/A004/A004123.seq | 5fb7125feeca93bf51642317535eed1b |
A004124 | Discriminant of n-th cyclotomic polynomial. | [
"1",
"1",
"-3",
"-4",
"125",
"-3",
"-16807",
"256",
"-19683",
"125",
"-2357947691",
"144",
"1792160394037",
"-16807",
"1265625",
"16777216",
"2862423051509815793",
"-19683",
"-5480386857784802185939",
"4000000",
"205924456521",
"-2357947691",
"-39471584120695485887249589623",
"5308416"
] | [
"sign",
"easy",
"nice"
] | 64 | 1 | 3 | null | [
"M2383"
] | N. J. A. Sloane | 2025-02-16T08:32:28 | oeisdata/seq/A004/A004124.seq | 7405b6f485bea33cf66e707519b4719e |
A004125 | Sum of remainders of n mod k, for k = 1, 2, 3, ..., n. | [
"0",
"0",
"1",
"1",
"4",
"3",
"8",
"8",
"12",
"13",
"22",
"17",
"28",
"31",
"36",
"36",
"51",
"47",
"64",
"61",
"70",
"77",
"98",
"85",
"103",
"112",
"125",
"124",
"151",
"138",
"167",
"167",
"184",
"197",
"218",
"198",
"233",
"248",
"269",
"258",
"297",
"284",
"325",
"328",
"339",
"358",
"403",
"374",
"414",
"420",
"449",
"454",
"505",
"492",
"529",
"520",
"553",
"578",
"635",
"586",
"645",
"672"
] | [
"nonn",
"easy",
"nice"
] | 169 | 1 | 5 | [
"A000290",
"A004125",
"A006218",
"A023196",
"A048158",
"A050482",
"A051778",
"A120444"
] | [
"M3213"
] | N. J. A. Sloane, Jeffrey Shallit | 2023-10-22T00:44:20 | oeisdata/seq/A004/A004125.seq | 71513d289b7f08b1a13f0e11f8ffcf3f |
A004126 | a(n) = n*(7*n^2 - 1)/6. | [
"0",
"1",
"9",
"31",
"74",
"145",
"251",
"399",
"596",
"849",
"1165",
"1551",
"2014",
"2561",
"3199",
"3935",
"4776",
"5729",
"6801",
"7999",
"9330",
"10801",
"12419",
"14191",
"16124",
"18225",
"20501",
"22959",
"25606",
"28449",
"31495",
"34751",
"38224",
"41921",
"45849",
"50015",
"54426",
"59089",
"64011"
] | [
"nonn",
"easy"
] | 62 | 0 | 3 | [
"A000217",
"A000292",
"A000447",
"A000566",
"A000578",
"A004006",
"A004068",
"A004126",
"A004188",
"A004466",
"A004467",
"A005900",
"A006003",
"A006527",
"A007588",
"A016993",
"A062025",
"A063521",
"A063522",
"A063523",
"A069099"
] | null | Albert D. Rich (AlbertRich(AT)msn.com) | 2022-09-08T08:44:32 | oeisdata/seq/A004/A004126.seq | db4a516da2cb62acab41973a9099fbf5 |
A004127 | Number of planar hexagon trees with n hexagons. | [
"1",
"1",
"3",
"12",
"68",
"483",
"3946",
"34485",
"315810",
"2984570",
"28907970",
"285601251",
"2868869733",
"29227904840",
"301430074416",
"3141985563575",
"33059739636198",
"350763452126835",
"3749420616902637",
"40348040718155170",
"436827335493148600"
] | [
"nonn"
] | 38 | 1 | 3 | [
"A002294",
"A004127",
"A005040",
"A005419",
"A143546",
"A221184",
"A295260",
"A369473"
] | [
"M2936"
] | N. J. A. Sloane | 2024-08-01T21:50:32 | oeisdata/seq/A004/A004127.seq | b3c16816466e091224faff97c41c6089 |
A004128 | a(n) = Sum_{k=1..n} floor(3*n/3^k). | [
"0",
"1",
"2",
"4",
"5",
"6",
"8",
"9",
"10",
"13",
"14",
"15",
"17",
"18",
"19",
"21",
"22",
"23",
"26",
"27",
"28",
"30",
"31",
"32",
"34",
"35",
"36",
"40",
"41",
"42",
"44",
"45",
"46",
"48",
"49",
"50",
"53",
"54",
"55",
"57",
"58",
"59",
"61",
"62",
"63",
"66",
"67",
"68",
"70",
"71",
"72",
"74",
"75",
"76",
"80",
"81",
"82",
"84",
"85",
"86",
"88",
"89",
"90",
"93",
"94",
"95",
"97",
"98",
"99",
"101",
"102"
] | [
"nonn"
] | 59 | 0 | 3 | [
"A001511",
"A004117",
"A004128",
"A005187",
"A051064",
"A054861",
"A054899",
"A055457",
"A067080",
"A098844",
"A132027"
] | null | N. J. A. Sloane | 2025-02-28T15:19:13 | oeisdata/seq/A004/A004128.seq | 2bfd224a0422440ba8f941d8db171073 |
A004129 | Postage stamp problem: largest m such that there exists an n-subset S of nonnegative integers such that 1,...,m can be expressed as a sum of two distinct elements of S. | [
"1",
"3",
"6",
"9",
"13",
"17",
"22",
"27",
"33",
"40",
"47",
"56",
"65",
"74",
"83",
"94",
"105"
] | [
"nonn",
"more"
] | 41 | 2 | 2 | null | [
"M2525"
] | N. J. A. Sloane | 2022-04-13T13:25:17 | oeisdata/seq/A004/A004129.seq | 5b2d1e8bd5f09610642486b90b3b1420 |
A004130 | Numerators in expansion of (1-x)^{-1/4}. | [
"1",
"1",
"5",
"15",
"195",
"663",
"4641",
"16575",
"480675",
"1762475",
"13042315",
"48612265",
"729183975",
"2748462675",
"20809788825",
"79077197535",
"4823709049635",
"18443593425075",
"141400882925575",
"543277076503525",
"8366466978154285",
"32270658344309385"
] | [
"nonn",
"frac"
] | 31 | 0 | 3 | [
"A000265",
"A004130",
"A004134",
"A004981",
"A007696",
"A034255",
"A034385",
"A048882",
"A049606"
] | null | N. J. A. Sloane | 2014-05-09T02:05:10 | oeisdata/seq/A004/A004130.seq | 08b531552f3023dffa31d9b0e0adaff0 |
A004131 | Modular postage stamp problem: largest m such that there exists an n-subset S of nonnegative integers such that 0,...,m-1 can be expressed as a mod-m sum of two distinct elements of S. | [
"1",
"3",
"6",
"9",
"13",
"17",
"24",
"30",
"36",
"42"
] | [
"nonn"
] | 26 | 2 | 2 | null | [
"M2527"
] | N. J. A. Sloane | 2021-01-15T16:48:43 | oeisdata/seq/A004/A004131.seq | bdee308ed469ec1c9ab9110cbe2242ce |
A004132 | Modular postage stamp problem. | [
"3",
"5",
"9",
"13",
"19",
"21",
"30",
"35",
"43",
"51",
"63",
"67"
] | [
"nonn",
"more"
] | 19 | 2 | 1 | null | [
"M2450"
] | N. J. A. Sloane | 2017-07-07T10:54:45 | oeisdata/seq/A004/A004132.seq | 4b78d3a43dbc0b73abd0452de9c3ef9f |
A004133 | Additive bases: a(n) is the least integer such that there is an n-element set of nonnegative integers, the sums of pairs (of distinct elements) of which are distinct and at most a(n). | [
"1",
"3",
"6",
"11",
"19",
"31",
"43",
"63",
"80",
"110",
"138",
"169",
"202",
"241",
"288",
"330"
] | [
"nonn",
"nice",
"more"
] | 51 | 2 | 2 | [
"A004133",
"A004135",
"A004136",
"A232234"
] | [
"M2544"
] | N. J. A. Sloane | 2020-05-04T10:52:35 | oeisdata/seq/A004/A004133.seq | 9bc1afc400c1dea8935513b1e8b8da0b |
A004134 | Denominators in expansion of (1-x)^{-1/4} are 2^a(n). | [
"0",
"2",
"5",
"7",
"11",
"13",
"16",
"18",
"23",
"25",
"28",
"30",
"34",
"36",
"39",
"41",
"47",
"49",
"52",
"54",
"58",
"60",
"63",
"65",
"70",
"72",
"75",
"77",
"81",
"83",
"86",
"88",
"95",
"97",
"100",
"102",
"106",
"108",
"111",
"113",
"118",
"120",
"123",
"125",
"129",
"131",
"134",
"136",
"142",
"144",
"147",
"149",
"153",
"155",
"158",
"160",
"165",
"167",
"170",
"172",
"176",
"178"
] | [
"nonn"
] | 26 | 0 | 2 | [
"A004130",
"A004134",
"A005187"
] | null | N. J. A. Sloane | 2015-08-04T03:49:30 | oeisdata/seq/A004/A004134.seq | f82876efba281d9e7b047229023987d3 |
A004135 | Additive bases: a(n) is the least integer k such that in the cyclic group Z_k there is a subset of n elements all pairs (of distinct elements) of which add up to a different sum (in Z_k). | [
"1",
"2",
"3",
"6",
"11",
"19",
"28",
"40",
"56",
"72",
"96",
"114",
"147",
"178",
"183",
"252",
"255"
] | [
"nonn",
"nice",
"more"
] | 39 | 1 | 2 | [
"A004133",
"A004135",
"A004136",
"A260998",
"A260999"
] | [
"M0782"
] | N. J. A. Sloane | 2020-02-02T20:09:33 | oeisdata/seq/A004/A004135.seq | 355ef5194b15834efce044ff6daaec36 |
A004136 | Additive bases: a(n) is the least integer k such that in the cyclic group Z_k there is a subset of n elements all pairs (of not necessarily distinct elements) of which add up to a different sum (in Z_k). | [
"1",
"3",
"7",
"13",
"21",
"31",
"48",
"57",
"73",
"91",
"120",
"133",
"168",
"183",
"255",
"255",
"273",
"307"
] | [
"nonn",
"nice",
"more"
] | 41 | 1 | 2 | [
"A003022",
"A004133",
"A004135",
"A004136",
"A260998",
"A260999"
] | [
"M2639"
] | N. J. A. Sloane | 2020-02-02T20:10:55 | oeisdata/seq/A004/A004136.seq | 58bfa4191462e0fe59e5915a199dd3d0 |
A004137 | Maximal number of edges in a graceful graph on n nodes. | [
"0",
"1",
"3",
"6",
"9",
"13",
"17",
"23",
"29",
"36",
"43",
"50",
"58",
"68",
"79",
"90",
"101",
"112",
"123",
"138",
"153",
"168",
"183",
"198",
"213",
"232"
] | [
"nonn",
"nice",
"hard",
"more"
] | 102 | 1 | 3 | [
"A004137",
"A005488",
"A046693",
"A080060",
"A102508",
"A103294",
"A103296",
"A103298",
"A103299",
"A212661",
"A289761"
] | [
"M2526"
] | N. J. A. Sloane, Simon Plouffe | 2025-02-16T08:32:28 | oeisdata/seq/A004/A004137.seq | f68baa887448cb99d032e6a79b228153 |
A004138 | From a counter moving problem. | [
"1",
"2",
"3",
"8",
"13",
"24",
"37",
"66",
"107",
"186",
"303",
"516",
"849",
"1436",
"2377",
"3998",
"6639",
"11134",
"18531",
"31024",
"51701",
"86464",
"144205",
"241018",
"402163",
"671906",
"1121463",
"1873244",
"3127129",
"5222724",
"8719537",
"14561622",
"24312695",
"40600230",
"67790379",
"113201160",
"189016701",
"315627944",
"527024245",
"880037810",
"1469467515"
] | [
"nonn",
"easy"
] | 34 | 1 | 2 | null | [
"M0872"
] | N. J. A. Sloane | 2023-10-25T09:30:29 | oeisdata/seq/A004/A004138.seq | 13ae26d459ee45898ca7206cec5df9e1 |
A004139 | Odd primes excluding 5. | [
"3",
"7",
"11",
"13",
"17",
"19",
"23",
"29",
"31",
"37",
"41",
"43",
"47",
"53",
"59",
"61",
"67",
"71",
"73",
"79",
"83",
"89",
"97",
"101",
"103",
"107",
"109",
"113",
"127",
"131",
"137",
"139",
"149",
"151",
"157",
"163",
"167",
"173",
"179",
"181",
"191",
"193",
"197",
"199",
"211",
"223",
"227",
"229",
"233",
"239",
"241"
] | [
"nonn",
"easy"
] | 24 | 1 | 1 | [
"A004139",
"A007401",
"A065091",
"A085837"
] | null | N. J. A. Sloane | 2019-12-16T00:30:44 | oeisdata/seq/A004/A004139.seq | e66f08c7e39a513aa4f543d324e55e4c |
A004140 | Number of nonempty labeled simple graphs on nodes chosen from an n-set. | [
"0",
"1",
"4",
"17",
"112",
"1449",
"40068",
"2350601",
"286192512",
"71213783665",
"35883905263780",
"36419649682706465",
"74221659280476136240",
"303193505953871645562969",
"2480118046704094643352358500",
"40601989176407026666590990422105",
"1329877330167226219547875498464516480"
] | [
"nonn",
"nice"
] | 45 | 0 | 3 | [
"A004140",
"A006896"
] | null | N. J. A. Sloane, Colin Mallows, James D. Klein | 2024-10-02T14:37:10 | oeisdata/seq/A004/A004140.seq | 95f767947c8e953369eabf8ca83b55eb |
A004141 | Norm of a matrix. | [
"1",
"2",
"8",
"48",
"256",
"1280",
"6912",
"39424",
"212992",
"1118208",
"6553600",
"36765696",
"199229440",
"1133117440",
"6499598336",
"36175872000",
"200655503360",
"1167945891840",
"6620826304512",
"36681168191488",
"212364657950720",
"1219998345330688",
"6864598984556544",
"38958828003262464",
"226089827240509440",
"1287455960675123200"
] | [
"nonn"
] | 27 | 1 | 2 | [
"A004141",
"A259868"
] | [
"M1876"
] | N. J. A. Sloane | 2023-10-24T20:26:34 | oeisdata/seq/A004/A004141.seq | 6f6a51ed29ff98f32595754e5c8557ba |
A004142 | a(n) = n*(3^n - 2^n). | [
"0",
"1",
"10",
"57",
"260",
"1055",
"3990",
"14413",
"50440",
"172539",
"580250",
"1926089",
"6328140",
"20619703",
"66732190",
"214742085",
"687698960",
"2193154547",
"6968850210",
"22073006401",
"69714716500",
"219623377071",
"690291036710"
] | [
"nonn",
"easy"
] | 12 | 0 | 3 | [
"A001047",
"A004142"
] | null | N. J. A. Sloane | 2023-10-24T20:29:23 | oeisdata/seq/A004/A004142.seq | e6b3a497944ac129691a2d636f69edc3 |
A004143 | From the powers that be. | [
"0",
"1",
"2",
"5",
"10",
"40",
"40",
"105",
"5627",
"14501",
"330861",
"658110",
"897229",
"26673531",
"180566007",
"180566007",
"19299107624"
] | [
"nonn",
"nice",
"more"
] | 48 | 1 | 3 | [
"A004143",
"A266162"
] | [
"M1386"
] | N. J. A. Sloane | 2018-12-27T03:17:11 | oeisdata/seq/A004/A004143.seq | e195a341ed037c49c20957562a3ebdb5 |
A004144 | Nonhypotenuse numbers (indices of positive squares that are not the sums of 2 distinct nonzero squares). | [
"1",
"2",
"3",
"4",
"6",
"7",
"8",
"9",
"11",
"12",
"14",
"16",
"18",
"19",
"21",
"22",
"23",
"24",
"27",
"28",
"31",
"32",
"33",
"36",
"38",
"42",
"43",
"44",
"46",
"47",
"48",
"49",
"54",
"56",
"57",
"59",
"62",
"63",
"64",
"66",
"67",
"69",
"71",
"72",
"76",
"77",
"79",
"81",
"83",
"84",
"86",
"88",
"92",
"93",
"94",
"96",
"98",
"99",
"103",
"107",
"108",
"112",
"114",
"118",
"121",
"124",
"126",
"127"
] | [
"nonn"
] | 85 | 1 | 2 | [
"A000290",
"A002145",
"A004144",
"A005089",
"A009003",
"A045326",
"A072437",
"A244659",
"A244662"
] | [
"M0542"
] | N. J. A. Sloane | 2025-02-16T08:32:28 | oeisdata/seq/A004/A004144.seq | 04896cd73c4c2c10973622f9a6437c83 |
A004145 | Number of degenerate simplices in n-cube. | [
"0",
"12",
"1360",
"350000",
"255036992",
"571462430224"
] | [
"nonn"
] | 12 | 2 | 2 | [
"A004145",
"A268408"
] | [
"M4881"
] | N. J. A. Sloane | 2023-10-24T20:29:59 | oeisdata/seq/A004/A004145.seq | 82b8333f850f2845c1458a3cffe0c718 |
A004146 | Alternate Lucas numbers - 2. | [
"0",
"1",
"5",
"16",
"45",
"121",
"320",
"841",
"2205",
"5776",
"15125",
"39601",
"103680",
"271441",
"710645",
"1860496",
"4870845",
"12752041",
"33385280",
"87403801",
"228826125",
"599074576",
"1568397605",
"4106118241",
"10749957120",
"28143753121",
"73681302245",
"192900153616",
"505019158605",
"1322157322201"
] | [
"nonn",
"easy"
] | 253 | 0 | 3 | [
"A000032",
"A001350",
"A002878",
"A004146",
"A005248",
"A027941",
"A032170",
"A074392",
"A092184",
"A100047",
"A103536",
"A158039",
"A158040",
"A158041",
"A158042",
"A158043",
"A158044"
] | [
"M3867"
] | N. J. A. Sloane | 2025-02-16T08:32:28 | oeisdata/seq/A004/A004146.seq | 3996687c4879c56c5d666f39bb8f286f |
A004147 | Number of n-state Turing machines which halt. | [
"32",
"9784",
"7571840",
"11140566368"
] | [
"nonn",
"nice",
"hard",
"bref"
] | 28 | 1 | 1 | [
"A004147",
"A028444",
"A052200"
] | [
"M5233"
] | N. J. A. Sloane | 2023-05-17T14:41:24 | oeisdata/seq/A004/A004147.seq | 60426c4dba9e20cc351b1476b70941d8 |
A004148 | Generalized Catalan numbers: a(n+1) = a(n) + Sum_{k=1..n-1} a(k)*a(n-1-k). | [
"1",
"1",
"1",
"2",
"4",
"8",
"17",
"37",
"82",
"185",
"423",
"978",
"2283",
"5373",
"12735",
"30372",
"72832",
"175502",
"424748",
"1032004",
"2516347",
"6155441",
"15101701",
"37150472",
"91618049",
"226460893",
"560954047",
"1392251012",
"3461824644",
"8622571758",
"21511212261",
"53745962199",
"134474581374"
] | [
"easy",
"nonn",
"nice"
] | 370 | 0 | 4 | [
"A000108",
"A001006",
"A004148",
"A004149",
"A046980",
"A051292",
"A064645",
"A088518",
"A131198"
] | [
"M1141"
] | N. J. A. Sloane | 2025-04-04T15:38:26 | oeisdata/seq/A004/A004148.seq | 0fd6afe9def098ae19808ac8d5d59665 |
A004149 | Generalized Catalan numbers: a(n+1) = a(n) + Sum_{k=2..n-1} a(k)*a(n-1-k). | [
"1",
"1",
"1",
"1",
"2",
"4",
"8",
"16",
"33",
"69",
"146",
"312",
"673",
"1463",
"3202",
"7050",
"15605",
"34705",
"77511",
"173779",
"390966",
"882376",
"1997211",
"4532593",
"10311720",
"23512376",
"53724350",
"122995968",
"282096693",
"648097855",
"1491322824",
"3436755328",
"7931085771"
] | [
"nonn",
"nice"
] | 113 | 0 | 5 | [
"A001006",
"A004148",
"A004149",
"A064645"
] | [
"M1131"
] | N. J. A. Sloane | 2025-01-27T10:14:23 | oeisdata/seq/A004/A004149.seq | 9b15206a7226f973848e26aec6549166 |
A004150 | Euler numbers written backwards. | [
"1",
"1",
"1",
"2",
"5",
"61",
"16",
"272",
"5831",
"6397",
"12505",
"297353",
"5672072",
"65286322",
"189063991",
"2137573091",
"54121519391",
"679243568902",
"1445769784042",
"23821158888092",
"525732881173073",
"6904213508941594",
"10973139347884396",
"2532586056883245101",
"50968075536143541551"
] | [
"nonn",
"base"
] | 16 | 0 | 4 | [
"A000111",
"A004086",
"A004150"
] | null | N. J. A. Sloane | 2025-02-22T19:14:23 | oeisdata/seq/A004/A004150.seq | 369814d345a761b198c6cca6219fcca1 |
A004151 | Omit trailing zeros from n. | [
"1",
"2",
"3",
"4",
"5",
"6",
"7",
"8",
"9",
"1",
"11",
"12",
"13",
"14",
"15",
"16",
"17",
"18",
"19",
"2",
"21",
"22",
"23",
"24",
"25",
"26",
"27",
"28",
"29",
"3",
"31",
"32",
"33",
"34",
"35",
"36",
"37",
"38",
"39",
"4",
"41",
"42",
"43",
"44",
"45",
"46",
"47",
"48",
"49",
"5",
"51",
"52",
"53",
"54",
"55",
"56",
"57",
"58",
"59",
"6",
"61",
"62",
"63",
"64",
"65",
"66",
"67",
"68",
"69",
"7",
"71",
"72",
"73",
"74",
"75",
"76",
"77",
"78",
"79",
"8",
"81",
"82",
"83",
"84",
"85",
"86",
"87",
"88",
"89",
"9",
"91",
"92",
"93",
"94",
"95",
"96",
"97",
"98",
"99",
"1",
"101",
"102",
"103",
"104",
"105",
"106",
"107",
"108",
"109",
"11",
"111",
"112",
"113",
"114",
"115",
"116",
"117",
"118",
"119",
"12"
] | [
"nonn",
"base",
"easy"
] | 43 | 1 | 2 | [
"A004151",
"A004719",
"A122840"
] | null | N. J. A. Sloane | 2024-02-21T01:25:25 | oeisdata/seq/A004/A004151.seq | aba032b6cfbc9452245c96105663f906 |
A004152 | Sum of digits of n!. | [
"1",
"1",
"2",
"6",
"6",
"3",
"9",
"9",
"9",
"27",
"27",
"36",
"27",
"27",
"45",
"45",
"63",
"63",
"54",
"45",
"54",
"63",
"72",
"99",
"81",
"72",
"81",
"108",
"90",
"126",
"117",
"135",
"108",
"144",
"144",
"144",
"171",
"153",
"108",
"189",
"189",
"144",
"189",
"180",
"216",
"207",
"216",
"225",
"234",
"225",
"216",
"198",
"279",
"279",
"261",
"279",
"333",
"270",
"288"
] | [
"nonn",
"base"
] | 86 | 0 | 3 | [
"A000142",
"A004152",
"A007953",
"A066419",
"A079584",
"A086358"
] | null | N. J. A. Sloane | 2024-08-26T11:42:56 | oeisdata/seq/A004/A004152.seq | ee96eba55efc1c56496139c38963c6bf |
A004153 | Factorial numbers written backwards. | [
"1",
"1",
"2",
"6",
"42",
"21",
"27",
"405",
"2304",
"88263",
"88263",
"861993",
"6100974",
"80207226",
"219287178",
"8634767031",
"88898722902",
"690824786553",
"8275073732046",
"238804001546121",
"466718002092342",
"4490717124909015",
"867067777270004211",
"4667948883761025852",
"63934932337104844026"
] | [
"nonn",
"base"
] | 23 | 0 | 3 | [
"A000142",
"A004086",
"A004153",
"A004192"
] | null | N. J. A. Sloane | 2023-12-28T07:07:57 | oeisdata/seq/A004/A004153.seq | f73588eb0757130458723ae66bb52247 |
A004154 | a(n) = n! with trailing zeros omitted. | [
"1",
"1",
"2",
"6",
"24",
"12",
"72",
"504",
"4032",
"36288",
"36288",
"399168",
"4790016",
"62270208",
"871782912",
"1307674368",
"20922789888",
"355687428096",
"6402373705728",
"121645100408832",
"243290200817664",
"5109094217170944",
"112400072777760768",
"2585201673888497664",
"62044840173323943936"
] | [
"nonn",
"base"
] | 49 | 0 | 3 | [
"A000142",
"A004151",
"A004154",
"A008904"
] | null | N. J. A. Sloane | 2025-04-11T14:27:31 | oeisdata/seq/A004/A004154.seq | b1a9ab02d3fcb938c7c4da4fbe079fd8 |
A004155 | Sum of digits of n-th odd number. | [
"1",
"3",
"5",
"7",
"9",
"2",
"4",
"6",
"8",
"10",
"3",
"5",
"7",
"9",
"11",
"4",
"6",
"8",
"10",
"12",
"5",
"7",
"9",
"11",
"13",
"6",
"8",
"10",
"12",
"14",
"7",
"9",
"11",
"13",
"15",
"8",
"10",
"12",
"14",
"16",
"9",
"11",
"13",
"15",
"17",
"10",
"12",
"14",
"16",
"18",
"2",
"4",
"6",
"8",
"10",
"3",
"5",
"7",
"9",
"11",
"4",
"6",
"8",
"10",
"12",
"5"
] | [
"nonn",
"base",
"easy"
] | 16 | 0 | 2 | [
"A004092",
"A004155",
"A007953"
] | null | N. J. A. Sloane | 2023-10-24T20:33:32 | oeisdata/seq/A004/A004155.seq | bf11094eea41b5f507670440693e14ef |
A004156 | Odd numbers written backwards. | [
"1",
"3",
"5",
"7",
"9",
"11",
"31",
"51",
"71",
"91",
"12",
"32",
"52",
"72",
"92",
"13",
"33",
"53",
"73",
"93",
"14",
"34",
"54",
"74",
"94",
"15",
"35",
"55",
"75",
"95",
"16",
"36",
"56",
"76",
"96",
"17",
"37",
"57",
"77",
"97",
"18",
"38",
"58",
"78",
"98",
"19",
"39",
"59",
"79",
"99",
"101",
"301",
"501",
"701",
"901",
"111",
"311",
"511",
"711",
"911",
"121",
"321",
"521"
] | [
"nonn",
"base"
] | 13 | 0 | 2 | [
"A004156",
"A005408"
] | null | N. J. A. Sloane | 2014-04-05T01:37:01 | oeisdata/seq/A004/A004156.seq | 91d125b0d1cdfedb82fe907270ba3145 |
A004157 | Sum of digits of n-th triangular number. | [
"0",
"1",
"3",
"6",
"1",
"6",
"3",
"10",
"9",
"9",
"10",
"12",
"15",
"10",
"6",
"3",
"10",
"9",
"9",
"10",
"3",
"6",
"10",
"15",
"3",
"10",
"9",
"18",
"10",
"12",
"15",
"19",
"15",
"12",
"19",
"9",
"18",
"10",
"12",
"15",
"10",
"15",
"12",
"19",
"18",
"9",
"10",
"12",
"15",
"10",
"15",
"12",
"19",
"9",
"18",
"10",
"21",
"15",
"10",
"15",
"12",
"19",
"18",
"9",
"10",
"12",
"6",
"19",
"15",
"12",
"19",
"18",
"18",
"10",
"21",
"15",
"19",
"6",
"12",
"10"
] | [
"nonn",
"base"
] | 26 | 0 | 3 | [
"A000217",
"A004157",
"A007953",
"A062688",
"A145389"
] | null | N. J. A. Sloane | 2024-03-31T15:31:07 | oeisdata/seq/A004/A004157.seq | 08e18db31c424f59dfa98811e2eb64f8 |
A004158 | Triangular numbers written backwards. | [
"0",
"1",
"3",
"6",
"1",
"51",
"12",
"82",
"63",
"54",
"55",
"66",
"87",
"19",
"501",
"21",
"631",
"351",
"171",
"91",
"12",
"132",
"352",
"672",
"3",
"523",
"153",
"873",
"604",
"534",
"564",
"694",
"825",
"165",
"595",
"36",
"666",
"307",
"147",
"87",
"28",
"168",
"309",
"649",
"99",
"5301",
"1801",
"8211",
"6711",
"5221",
"5721",
"6231",
"8731",
"1341",
"5841",
"451"
] | [
"nonn",
"base",
"look"
] | 23 | 0 | 3 | null | null | N. J. A. Sloane | 2022-09-08T08:44:32 | oeisdata/seq/A004/A004158.seq | c15b550d6b6e0a6ed4f50aaa4b4193be |
A004159 | Sum of digits of n^2. | [
"0",
"1",
"4",
"9",
"7",
"7",
"9",
"13",
"10",
"9",
"1",
"4",
"9",
"16",
"16",
"9",
"13",
"19",
"9",
"10",
"4",
"9",
"16",
"16",
"18",
"13",
"19",
"18",
"19",
"13",
"9",
"16",
"7",
"18",
"13",
"10",
"18",
"19",
"13",
"9",
"7",
"16",
"18",
"22",
"19",
"9",
"10",
"13",
"9",
"7",
"7",
"9",
"13",
"19",
"18",
"10",
"13",
"18",
"16",
"16",
"9",
"13",
"19",
"27",
"19",
"13",
"18",
"25",
"16",
"18",
"13",
"10",
"18",
"19",
"22",
"18",
"25",
"25",
"18",
"13"
] | [
"nonn",
"base"
] | 64 | 0 | 3 | [
"A004159",
"A007953",
"A056691",
"A062685",
"A071317",
"A159918",
"A240752",
"A268226"
] | null | N. J. A. Sloane | 2021-11-12T12:23:37 | oeisdata/seq/A004/A004159.seq | 80f169893b212e3844d7c0c80663b05e |
A004160 | Sum of digits of the n-th tetrahedral number. | [
"1",
"4",
"1",
"2",
"8",
"11",
"12",
"3",
"12",
"4",
"16",
"13",
"14",
"11",
"14",
"15",
"24",
"6",
"7",
"10",
"16",
"8",
"5",
"8",
"18",
"18",
"18",
"10",
"22",
"19",
"20",
"26",
"20",
"12",
"21",
"21",
"22",
"25",
"13",
"14",
"11",
"14",
"15",
"15",
"15",
"25",
"19",
"16",
"17",
"5",
"17",
"18",
"18",
"18",
"19",
"22",
"19",
"11",
"26",
"20",
"21",
"21",
"21",
"22",
"25",
"13",
"23",
"20",
"23",
"24",
"24",
"24",
"25",
"10",
"16",
"26"
] | [
"nonn",
"base",
"easy"
] | 17 | 1 | 2 | [
"A000292",
"A004160",
"A007953"
] | null | N. J. A. Sloane | 2023-10-24T23:16:25 | oeisdata/seq/A004/A004160.seq | 3eb0785e191319ab65a697227b3ad75a |
A004161 | Tetrahedral numbers written backwards. | [
"0",
"1",
"4",
"1",
"2",
"53",
"65",
"48",
"21",
"561",
"22",
"682",
"463",
"554",
"65",
"86",
"618",
"969",
"411",
"331",
"451",
"1771",
"4202",
"32",
"62",
"5292",
"6723",
"4563",
"604",
"5944",
"694",
"6545",
"4895",
"5456",
"417",
"777",
"6348",
"9319",
"889",
"6601",
"8411",
"14321",
"44231",
"9141",
"8151",
"51261",
"69271",
"42481",
"691",
"52802"
] | [
"nonn",
"base",
"look"
] | 13 | 0 | 3 | [
"A000292",
"A004161"
] | null | N. J. A. Sloane | 2015-04-09T11:07:08 | oeisdata/seq/A004/A004161.seq | 20f95f22cfa0126dd121fb075e1dcff7 |
A004162 | Sum of digits of pentagonal numbers. | [
"1",
"5",
"3",
"4",
"8",
"6",
"7",
"11",
"9",
"10",
"14",
"3",
"13",
"17",
"6",
"16",
"11",
"18",
"10",
"14",
"12",
"13",
"17",
"15",
"16",
"2",
"9",
"10",
"14",
"12",
"13",
"8",
"15",
"16",
"11",
"18",
"10",
"14",
"12",
"13",
"8",
"15",
"16",
"20",
"9",
"10",
"14",
"12",
"22",
"17",
"24",
"7",
"20",
"18",
"10",
"23",
"21",
"13",
"17",
"15",
"16",
"20",
"18",
"10",
"14",
"12",
"13",
"17",
"15",
"16",
"20",
"18",
"28",
"23",
"12",
"22",
"26"
] | [
"nonn",
"base"
] | 8 | 1 | 2 | [
"A000326",
"A004162"
] | null | N. J. A. Sloane | 2021-12-26T20:51:45 | oeisdata/seq/A004/A004162.seq | a0dfca45d185475d79938c382328b035 |
A004163 | Pentagonal numbers written backwards. | [
"0",
"1",
"5",
"21",
"22",
"53",
"15",
"7",
"29",
"711",
"541",
"671",
"12",
"742",
"782",
"33",
"673",
"524",
"774",
"235",
"95",
"156",
"517",
"287",
"258",
"529",
"1001",
"801",
"2611",
"7421",
"5331",
"6241",
"251",
"7161",
"7171",
"281",
"6291",
"5302",
"7412",
"2622",
"832",
"1052",
"5262",
"2572",
"2882",
"5103",
"1513",
"923",
"2343",
"7753",
"5273"
] | [
"nonn",
"base"
] | 13 | 0 | 3 | [
"A000326",
"A004163"
] | null | N. J. A. Sloane | 2015-04-09T11:10:19 | oeisdata/seq/A004/A004163.seq | bed5fe55c3c6e70738f58d696a131a7b |
A004164 | Sum of digits of n^3. | [
"0",
"1",
"8",
"9",
"10",
"8",
"9",
"10",
"8",
"18",
"1",
"8",
"18",
"19",
"17",
"18",
"19",
"17",
"18",
"28",
"8",
"18",
"19",
"17",
"18",
"19",
"26",
"27",
"19",
"26",
"9",
"28",
"26",
"27",
"19",
"26",
"27",
"19",
"26",
"27",
"10",
"26",
"27",
"28",
"26",
"18",
"28",
"17",
"18",
"28",
"8",
"18",
"19",
"35",
"27",
"28",
"26",
"27",
"19",
"26",
"9",
"28",
"26",
"18",
"19",
"26",
"36",
"19"
] | [
"nonn",
"easy",
"base"
] | 21 | 0 | 3 | [
"A004159",
"A004164",
"A007953"
] | null | N. J. A. Sloane | 2024-07-19T10:10:59 | oeisdata/seq/A004/A004164.seq | 2cb6148e112f451a15f44ad034c777c5 |
A004165 | Cubes written backwards. | [
"1",
"8",
"72",
"46",
"521",
"612",
"343",
"215",
"927",
"1",
"1331",
"8271",
"7912",
"4472",
"5733",
"6904",
"3194",
"2385",
"9586",
"8",
"1629",
"84601",
"76121",
"42831",
"52651",
"67571",
"38691",
"25912",
"98342",
"72",
"19792",
"86723",
"73953",
"40393",
"57824",
"65664",
"35605",
"27845",
"91395",
"46",
"12986",
"88047",
"70597",
"48158"
] | [
"nonn",
"base"
] | 32 | 1 | 2 | [
"A000578",
"A002942",
"A004086",
"A004165"
] | null | N. J. A. Sloane | 2023-12-28T07:08:01 | oeisdata/seq/A004/A004165.seq | aa207775273b61731371e1dc34d1236d |
A004166 | Sum of digits of 3^n. | [
"1",
"3",
"9",
"9",
"9",
"9",
"18",
"18",
"18",
"27",
"27",
"27",
"18",
"27",
"45",
"36",
"27",
"27",
"45",
"36",
"45",
"27",
"45",
"54",
"54",
"63",
"63",
"81",
"72",
"72",
"63",
"81",
"63",
"72",
"99",
"81",
"81",
"90",
"90",
"81",
"90",
"99",
"90",
"108",
"90",
"99",
"108",
"126",
"117",
"108",
"144",
"117",
"117",
"135",
"108",
"90",
"90",
"108",
"126",
"117",
"99"
] | [
"nonn",
"base"
] | 52 | 0 | 2 | [
"A001370",
"A004166",
"A065713",
"A065999",
"A066001",
"A066002",
"A066003",
"A066004",
"A066005",
"A066006",
"A067500",
"A118872",
"A175435",
"A175527"
] | null | N. J. A. Sloane | 2023-10-24T20:36:13 | oeisdata/seq/A004/A004166.seq | 83fc536683a239cd7347a1f6998c7f5e |
A004167 | Powers of 3 written backwards. | [
"1",
"3",
"9",
"72",
"18",
"342",
"927",
"7812",
"1656",
"38691",
"94095",
"741771",
"144135",
"3234951",
"9692874",
"70984341",
"12764034",
"361041921",
"984024783",
"7641622611",
"1044876843",
"30235306401",
"90695018313",
"72887134149",
"184635924282",
"344906882748",
"9238285681452",
"7894847955267"
] | [
"nonn",
"base",
"easy"
] | 24 | 0 | 2 | [
"A000079",
"A000244",
"A004094",
"A004167",
"A028909",
"A028910",
"A036447",
"A057615",
"A163632",
"A263451",
"A321539",
"A321540",
"A321541",
"A321542"
] | null | N. J. A. Sloane | 2021-02-19T13:44:37 | oeisdata/seq/A004/A004167.seq | 82dee5fde933eb756f93e85c14795f5c |
A004168 | a(n+1) = a(n)*(a(n)+1). | [
"3",
"12",
"156",
"24492",
"599882556",
"359859081592975692",
"129498558604939936868397356895854556",
"16769876680757063368089314196389622249367851612542961252860614401811692"
] | [
"nonn",
"easy"
] | 28 | 0 | 1 | [
"A000058",
"A004168",
"A007018"
] | null | N. J. A. Sloane | 2023-10-24T20:37:35 | oeisdata/seq/A004/A004168.seq | 92787feee1526653b9a51f4eed0badf9 |
A004169 | Values of m for which a regular polygon with m sides cannot be constructed with ruler and compass. | [
"7",
"9",
"11",
"13",
"14",
"18",
"19",
"21",
"22",
"23",
"25",
"26",
"27",
"28",
"29",
"31",
"33",
"35",
"36",
"37",
"38",
"39",
"41",
"42",
"43",
"44",
"45",
"46",
"47",
"49",
"50",
"52",
"53",
"54",
"55",
"56",
"57",
"58",
"59",
"61",
"62",
"63",
"65",
"66",
"67",
"69",
"70",
"71",
"72",
"73",
"74",
"75",
"76",
"77",
"78",
"79",
"81",
"82",
"83",
"84",
"86",
"87",
"88",
"89",
"90",
"91"
] | [
"nonn",
"nice"
] | 43 | 1 | 1 | [
"A000010",
"A003401",
"A004169",
"A130880",
"A209229",
"A255241",
"A272487",
"A272488",
"A272489",
"A272490",
"A272491"
] | null | N. J. A. Sloane, Branislav Kisacanin (bkisacan(AT)eecs.uic.edu) | 2023-02-23T10:40:27 | oeisdata/seq/A004/A004169.seq | 03081339730e063394283ea0b50dedf1 |
A004170 | Reversals of Fibonacci numbers (sorted). | [
"0",
"1",
"1",
"2",
"3",
"5",
"8",
"12",
"16",
"31",
"43",
"55",
"98",
"332",
"441",
"773",
"789",
"1814",
"4852",
"5676",
"7951",
"11771",
"40238",
"52057",
"64901",
"75682",
"86364",
"118713",
"393121",
"814691",
"922415",
"5647229",
"7882075",
"8754253",
"9038712",
"9626431"
] | [
"nonn",
"base",
"easy",
"nice"
] | 23 | 0 | 4 | [
"A000045",
"A004086",
"A004091",
"A004170",
"A214855"
] | null | N. J. A. Sloane | 2024-12-04T10:35:49 | oeisdata/seq/A004/A004170.seq | 8019570335fd5dfa09057009e7ef21a4 |
A004171 | a(n) = 2^(2n+1). | [
"2",
"8",
"32",
"128",
"512",
"2048",
"8192",
"32768",
"131072",
"524288",
"2097152",
"8388608",
"33554432",
"134217728",
"536870912",
"2147483648",
"8589934592",
"34359738368",
"137438953472",
"549755813888",
"2199023255552",
"8796093022208",
"35184372088832",
"140737488355328",
"562949953421312"
] | [
"easy",
"nonn"
] | 132 | 0 | 1 | [
"A000980",
"A004171",
"A009117",
"A013708",
"A013729",
"A013776",
"A081294",
"A132020",
"A164632",
"A181765"
] | null | N. J. A. Sloane | 2025-02-16T08:32:28 | oeisdata/seq/A004/A004171.seq | 8f328701aa090c0bc68fdc4da72d1870 |
A004172 | Triangle of coefficients of Euler polynomials E_2n(x) (exponents in increasing order). | [
"1",
"0",
"-1",
"1",
"0",
"1",
"0",
"-2",
"1",
"0",
"-3",
"0",
"5",
"0",
"-3",
"1",
"0",
"17",
"0",
"-28",
"0",
"14",
"0",
"-4",
"1",
"0",
"-155",
"0",
"255",
"0",
"-126",
"0",
"30",
"0",
"-5",
"1",
"0",
"2073",
"0",
"-3410",
"0",
"1683",
"0",
"-396",
"0",
"55",
"0",
"-6",
"1",
"0",
"-38227",
"0",
"62881",
"0",
"-31031",
"0",
"7293",
"0",
"-1001",
"0",
"91",
"0",
"-7",
"1",
"0",
"929569",
"0"
] | [
"sign",
"tabl",
"nice"
] | 26 | 0 | 8 | [
"A004172",
"A060083"
] | null | N. J. A. Sloane | 2025-02-16T08:32:28 | oeisdata/seq/A004/A004172.seq | ffaabf6b59cc4693dc75e5b6960f1e67 |
A004173 | Triangle of coefficients of Euler polynomials E_2n(x) (exponents in decreasing order). | [
"1",
"1",
"-1",
"0",
"1",
"-2",
"0",
"1",
"0",
"1",
"-3",
"0",
"5",
"0",
"-3",
"0",
"1",
"-4",
"0",
"14",
"0",
"-28",
"0",
"17",
"0",
"1",
"-5",
"0",
"30",
"0",
"-126",
"0",
"255",
"0",
"-155",
"0",
"1",
"-6",
"0",
"55",
"0",
"-396",
"0",
"1683",
"0",
"-3410",
"0",
"2073",
"0",
"1",
"-7",
"0",
"91",
"0",
"-1001",
"0",
"7293",
"0",
"-31031",
"0",
"62881",
"0",
"-38227",
"0",
"1",
"-8",
"0",
"140",
"0"
] | [
"sign",
"tabf",
"nice"
] | 26 | 0 | 6 | [
"A004173",
"A060082"
] | null | N. J. A. Sloane, corrected Jan 09 2007 | 2025-02-16T08:32:28 | oeisdata/seq/A004/A004173.seq | dbe65bb2b4caeebd60d90683ec0ec1b0 |
A004174 | Triangle of coefficients of Euler polynomials 2^n*E_n(x) (exponents in increasing order). | [
"1",
"-1",
"2",
"0",
"-4",
"4",
"2",
"0",
"-12",
"8",
"0",
"16",
"0",
"-32",
"16",
"-16",
"0",
"80",
"0",
"-80",
"32",
"0",
"-192",
"0",
"320",
"0",
"-192",
"64",
"272",
"0",
"-1344",
"0",
"1120",
"0",
"-448",
"128",
"0",
"4352",
"0",
"-7168",
"0",
"3584",
"0",
"-1024",
"256",
"-7936",
"0",
"39168",
"0",
"-32256",
"0",
"10752",
"0",
"-2304",
"512",
"0",
"-158720",
"0"
] | [
"sign",
"tabl",
"nice"
] | 26 | 0 | 3 | [
"A004174",
"A099932"
] | null | N. J. A. Sloane | 2025-02-16T08:32:28 | oeisdata/seq/A004/A004174.seq | 9fc2257f81cbd9933b344c68f786725e |
A004175 | Triangle of coefficients of Euler polynomials 2^n*E_n(x) (exponents in decreasing order). | [
"1",
"2",
"-1",
"4",
"-4",
"0",
"8",
"-12",
"0",
"2",
"16",
"-32",
"0",
"16",
"0",
"32",
"-80",
"0",
"80",
"0",
"-16",
"64",
"-192",
"0",
"320",
"0",
"-192",
"0",
"128",
"-448",
"0",
"1120",
"0",
"-1344",
"0",
"272",
"256",
"-1024",
"0",
"3584",
"0",
"-7168",
"0",
"4352",
"0",
"512",
"-2304",
"0",
"10752",
"0",
"-32256",
"0",
"39168",
"0",
"-7936",
"1024"
] | [
"sign",
"tabl",
"nice",
"easy"
] | 18 | 0 | 2 | null | null | N. J. A. Sloane | 2022-01-31T01:30:04 | oeisdata/seq/A004/A004175.seq | 4b578a54a4c0787f91861b0a7a861641 |
A004176 | Omit 1's from n. | [
"0",
"0",
"2",
"3",
"4",
"5",
"6",
"7",
"8",
"9",
"0",
"0",
"2",
"3",
"4",
"5",
"6",
"7",
"8",
"9",
"20",
"2",
"22",
"23",
"24",
"25",
"26",
"27",
"28",
"29",
"30",
"3",
"32",
"33",
"34",
"35",
"36",
"37",
"38",
"39",
"40",
"4",
"42",
"43",
"44",
"45",
"46",
"47",
"48",
"49",
"50",
"5",
"52",
"53",
"54",
"55",
"56",
"57",
"58",
"59",
"60",
"6",
"62",
"63",
"64",
"65",
"66",
"67",
"68",
"69",
"70",
"7",
"72",
"73",
"74"
] | [
"nonn",
"base",
"look"
] | 24 | 0 | 3 | [
"A004176",
"A004720",
"A359510"
] | null | N. J. A. Sloane | 2023-10-24T20:38:21 | oeisdata/seq/A004/A004176.seq | 1fe3e97a910b90d4bda8fbcd10d5d093 |
A004177 | Omit 2's from n. | [
"0",
"1",
"0",
"3",
"4",
"5",
"6",
"7",
"8",
"9",
"10",
"11",
"1",
"13",
"14",
"15",
"16",
"17",
"18",
"19",
"0",
"1",
"0",
"3",
"4",
"5",
"6",
"7",
"8",
"9",
"30",
"31",
"3",
"33",
"34",
"35",
"36",
"37",
"38",
"39",
"40",
"41",
"4",
"43",
"44",
"45",
"46",
"47",
"48",
"49",
"50",
"51",
"5",
"53",
"54",
"55",
"56",
"57",
"58",
"59",
"60",
"61",
"6",
"63",
"64",
"65",
"66",
"67",
"68",
"69",
"70",
"71",
"7",
"73",
"74"
] | [
"nonn",
"base",
"look"
] | 17 | 0 | 4 | [
"A004176",
"A004177",
"A004178",
"A004179",
"A004180",
"A004181",
"A004182",
"A004183",
"A004184",
"A004719"
] | null | N. J. A. Sloane | 2024-09-16T09:22:50 | oeisdata/seq/A004/A004177.seq | 6eadb3fb7d4581c2b5e9f97dc08bc2d4 |
A004178 | Omit 3's from n. | [
"0",
"1",
"2",
"0",
"4",
"5",
"6",
"7",
"8",
"9",
"10",
"11",
"12",
"1",
"14",
"15",
"16",
"17",
"18",
"19",
"20",
"21",
"22",
"2",
"24",
"25",
"26",
"27",
"28",
"29",
"0",
"1",
"2",
"0",
"4",
"5",
"6",
"7",
"8",
"9",
"40",
"41",
"42",
"4",
"44",
"45",
"46",
"47",
"48",
"49",
"50",
"51",
"52",
"5",
"54",
"55",
"56",
"57",
"58",
"59",
"60",
"61",
"62",
"6",
"64",
"65",
"66",
"67",
"68",
"69",
"70",
"71",
"72",
"7",
"74"
] | [
"nonn",
"base",
"easy"
] | 14 | 0 | 3 | [
"A004178",
"A004722",
"A052405"
] | null | N. J. A. Sloane | 2023-10-24T20:39:04 | oeisdata/seq/A004/A004178.seq | 42cb6d48c09d24e5c4464fe55336f78f |
A004179 | Omit 4's from n. | [
"0",
"1",
"2",
"3",
"0",
"5",
"6",
"7",
"8",
"9",
"10",
"11",
"12",
"13",
"1",
"15",
"16",
"17",
"18",
"19",
"20",
"21",
"22",
"23",
"2",
"25",
"26",
"27",
"28",
"29",
"30",
"31",
"32",
"33",
"3",
"35",
"36",
"37",
"38",
"39",
"0",
"1",
"2",
"3",
"0",
"5",
"6",
"7",
"8",
"9",
"50",
"51",
"52",
"53",
"5",
"55",
"56",
"57",
"58",
"59",
"60",
"61",
"62",
"63",
"6",
"65",
"66",
"67",
"68",
"69",
"70",
"71",
"72",
"73",
"7"
] | [
"nonn",
"base",
"easy"
] | 15 | 0 | 3 | null | null | N. J. A. Sloane | 2019-05-22T03:35:15 | oeisdata/seq/A004/A004179.seq | 41ffd433737868d7fac12af3edeeea37 |
A004180 | Omit 5's from n. | [
"0",
"1",
"2",
"3",
"4",
"0",
"6",
"7",
"8",
"9",
"10",
"11",
"12",
"13",
"14",
"1",
"16",
"17",
"18",
"19",
"20",
"21",
"22",
"23",
"24",
"2",
"26",
"27",
"28",
"29",
"30",
"31",
"32",
"33",
"34",
"3",
"36",
"37",
"38",
"39",
"40",
"41",
"42",
"43",
"44",
"4",
"46",
"47",
"48",
"49",
"0",
"1",
"2",
"3",
"4",
"0",
"6",
"7",
"8",
"9",
"60",
"61",
"62",
"63",
"64",
"6",
"66",
"67",
"68",
"69",
"70",
"71",
"72",
"73",
"74"
] | [
"nonn",
"base",
"easy"
] | 18 | 0 | 3 | [
"A004180",
"A004724"
] | null | N. J. A. Sloane | 2020-01-14T05:32:35 | oeisdata/seq/A004/A004180.seq | c477628cbc4b554a3b8da4f8677ed735 |
A004181 | Omit 6's from n. | [
"0",
"1",
"2",
"3",
"4",
"5",
"0",
"7",
"8",
"9",
"10",
"11",
"12",
"13",
"14",
"15",
"1",
"17",
"18",
"19",
"20",
"21",
"22",
"23",
"24",
"25",
"2",
"27",
"28",
"29",
"30",
"31",
"32",
"33",
"34",
"35",
"3",
"37",
"38",
"39",
"40",
"41",
"42",
"43",
"44",
"45",
"4",
"47",
"48",
"49",
"50",
"51",
"52",
"53",
"54",
"55",
"5",
"57",
"58",
"59",
"0",
"1",
"2",
"3",
"4",
"5",
"0",
"7",
"8",
"9",
"70",
"71",
"72",
"73",
"74"
] | [
"nonn",
"base"
] | 6 | 0 | 3 | null | null | N. J. A. Sloane | 2023-10-24T20:40:19 | oeisdata/seq/A004/A004181.seq | 96c30a3b6e5a88393217a95b9037db4f |
A004182 | Omit 7's from n. | [
"0",
"1",
"2",
"3",
"4",
"5",
"6",
"0",
"8",
"9",
"10",
"11",
"12",
"13",
"14",
"15",
"16",
"1",
"18",
"19",
"20",
"21",
"22",
"23",
"24",
"25",
"26",
"2",
"28",
"29",
"30",
"31",
"32",
"33",
"34",
"35",
"36",
"3",
"38",
"39",
"40",
"41",
"42",
"43",
"44",
"45",
"46",
"4",
"48",
"49",
"50",
"51",
"52",
"53",
"54",
"55",
"56",
"5",
"58",
"59",
"60",
"61",
"62",
"63",
"64",
"65",
"66",
"6",
"68",
"69",
"0",
"1",
"2"
] | [
"nonn",
"base"
] | 11 | 0 | 3 | null | null | N. J. A. Sloane | 2024-02-13T16:57:54 | oeisdata/seq/A004/A004182.seq | 7c6fb68d657e5dadffb2f75b2dcfbe1b |
A004183 | Omit 8's from n. | [
"0",
"1",
"2",
"3",
"4",
"5",
"6",
"7",
"0",
"9",
"10",
"11",
"12",
"13",
"14",
"15",
"16",
"17",
"1",
"19",
"20",
"21",
"22",
"23",
"24",
"25",
"26",
"27",
"2",
"29",
"30",
"31",
"32",
"33",
"34",
"35",
"36",
"37",
"3",
"39",
"40",
"41",
"42",
"43",
"44",
"45",
"46",
"47",
"4",
"49",
"50",
"51",
"52",
"53",
"54",
"55",
"56",
"57",
"5",
"59",
"60",
"61",
"62",
"63",
"64",
"65",
"66",
"67",
"6",
"69",
"70",
"71"
] | [
"nonn",
"base"
] | 6 | 0 | 3 | null | null | N. J. A. Sloane | 2023-10-24T20:40:47 | oeisdata/seq/A004/A004183.seq | b66febf5cd43c3cc689feb4b86d1dca6 |
A004184 | Omit 9's from n. | [
"0",
"1",
"2",
"3",
"4",
"5",
"6",
"7",
"8",
"0",
"10",
"11",
"12",
"13",
"14",
"15",
"16",
"17",
"18",
"1",
"20",
"21",
"22",
"23",
"24",
"25",
"26",
"27",
"28",
"2",
"30",
"31",
"32",
"33",
"34",
"35",
"36",
"37",
"38",
"3",
"40",
"41",
"42",
"43",
"44",
"45",
"46",
"47",
"48",
"4",
"50",
"51",
"52",
"53",
"54",
"55",
"56",
"57",
"58",
"5",
"60",
"61",
"62",
"63",
"64",
"65",
"66",
"67",
"68",
"6",
"70",
"71"
] | [
"nonn",
"base"
] | 6 | 0 | 3 | null | null | N. J. A. Sloane | 2023-10-24T20:41:03 | oeisdata/seq/A004/A004184.seq | d39b821fb1a7439c504e20da4cedf011 |
A004185 | Arrange digits of n in increasing order, then (for n > 0) omit the zeros. | [
"0",
"1",
"2",
"3",
"4",
"5",
"6",
"7",
"8",
"9",
"1",
"11",
"12",
"13",
"14",
"15",
"16",
"17",
"18",
"19",
"2",
"12",
"22",
"23",
"24",
"25",
"26",
"27",
"28",
"29",
"3",
"13",
"23",
"33",
"34",
"35",
"36",
"37",
"38",
"39",
"4",
"14",
"24",
"34",
"44",
"45",
"46",
"47",
"48",
"49",
"5",
"15",
"25",
"35",
"45",
"55",
"56",
"57",
"58",
"59",
"6",
"16",
"26",
"36",
"46",
"56",
"66",
"67",
"68",
"69",
"7",
"17",
"27",
"37",
"47"
] | [
"nonn",
"base",
"nice",
"easy",
"look"
] | 61 | 0 | 3 | [
"A004086",
"A004151",
"A004185",
"A004186",
"A004719",
"A009996",
"A065641",
"A073138",
"A086042",
"A193581",
"A193582",
"A211654",
"A221714"
] | null | N. J. A. Sloane | 2022-09-08T08:44:32 | oeisdata/seq/A004/A004185.seq | cbb73931d466a98fa7e63ebb53535332 |
A004186 | Arrange digits of n in decreasing order. | [
"0",
"1",
"2",
"3",
"4",
"5",
"6",
"7",
"8",
"9",
"10",
"11",
"21",
"31",
"41",
"51",
"61",
"71",
"81",
"91",
"20",
"21",
"22",
"32",
"42",
"52",
"62",
"72",
"82",
"92",
"30",
"31",
"32",
"33",
"43",
"53",
"63",
"73",
"83",
"93",
"40",
"41",
"42",
"43",
"44",
"54",
"64",
"74",
"84",
"94",
"50",
"51",
"52",
"53",
"54",
"55",
"65",
"75",
"85",
"95",
"60",
"61",
"62",
"63",
"64",
"65",
"66",
"76",
"86",
"96",
"70",
"71",
"72"
] | [
"nonn",
"base",
"look",
"easy"
] | 49 | 0 | 3 | [
"A004086",
"A004185",
"A004186",
"A009996",
"A028907",
"A028908",
"A032553",
"A032554",
"A064222",
"A194233"
] | null | N. J. A. Sloane | 2024-08-07T10:36:28 | oeisdata/seq/A004/A004186.seq | 0fea03101bc1177dd8800b928f2e905c |
A004187 | a(n) = 7*a(n-1) - a(n-2) with a(0) = 0, a(1) = 1. | [
"0",
"1",
"7",
"48",
"329",
"2255",
"15456",
"105937",
"726103",
"4976784",
"34111385",
"233802911",
"1602508992",
"10983760033",
"75283811239",
"516002918640",
"3536736619241",
"24241153416047",
"166151337293088",
"1138818207635569",
"7805576116155895",
"53500214605455696",
"366695926122033977"
] | [
"nonn",
"easy"
] | 181 | 0 | 3 | [
"A000027",
"A001109",
"A001353",
"A001906",
"A004187",
"A004254",
"A028412",
"A033888",
"A049685",
"A056854"
] | null | N. J. A. Sloane, R. K. Guy | 2025-01-05T19:51:33 | oeisdata/seq/A004/A004187.seq | 89759a2f160a36b3d7b0a6bf16aa7f2d |
A004188 | a(n) = n*(3*n^2 - 1)/2. | [
"0",
"1",
"11",
"39",
"94",
"185",
"321",
"511",
"764",
"1089",
"1495",
"1991",
"2586",
"3289",
"4109",
"5055",
"6136",
"7361",
"8739",
"10279",
"11990",
"13881",
"15961",
"18239",
"20724",
"23425",
"26351",
"29511",
"32914",
"36569",
"40485",
"44671",
"49136",
"53889",
"58939",
"64295",
"69966",
"75961"
] | [
"nonn",
"easy"
] | 56 | 0 | 3 | [
"A000447",
"A000578",
"A002412",
"A004006",
"A004068",
"A004126",
"A004188",
"A004466",
"A004467",
"A005900",
"A006003",
"A006527",
"A007588",
"A016061",
"A051682",
"A062025",
"A063521",
"A063522",
"A063523",
"A236770"
] | null | Albert D. Rich (AlbertRich(AT)msn.com) | 2022-09-08T08:44:32 | oeisdata/seq/A004/A004188.seq | f0d54a9dfda7880d8619949caffac802 |
A004189 | a(n) = 10*a(n-1) - a(n-2); a(0) = 0, a(1) = 1. | [
"0",
"1",
"10",
"99",
"980",
"9701",
"96030",
"950599",
"9409960",
"93149001",
"922080050",
"9127651499",
"90354434940",
"894416697901",
"8853812544070",
"87643708742799",
"867583274883920",
"8588189040096401",
"85014307126080090",
"841554882220704499",
"8330534515080964900",
"82463790268588944501",
"816307368170808480110"
] | [
"easy",
"nonn"
] | 176 | 0 | 3 | [
"A000027",
"A001079",
"A001090",
"A001109",
"A001353",
"A001906",
"A004187",
"A004189",
"A004191",
"A004254",
"A007655",
"A018913",
"A029547",
"A029548",
"A046173",
"A049310",
"A049660",
"A054320",
"A072256",
"A075843",
"A077412",
"A077421",
"A077423",
"A078987",
"A097309",
"A097311",
"A097313",
"A097316",
"A101950",
"A105138",
"A108741",
"A144128",
"A323182"
] | null | N. J. A. Sloane | 2025-01-05T19:51:33 | oeisdata/seq/A004/A004189.seq | e8329ea5f6530d0479cf69994dc88d7a |
A004190 | Expansion of 1/(1 - 11*x + x^2). | [
"1",
"11",
"120",
"1309",
"14279",
"155760",
"1699081",
"18534131",
"202176360",
"2205405829",
"24057287759",
"262424759520",
"2862615066961",
"31226340977051",
"340627135680600",
"3715672151509549",
"40531766530924439",
"442133759688659280",
"4822939590044327641",
"52610201730798944771",
"573889279448744064840"
] | [
"nonn",
"easy"
] | 105 | 0 | 2 | [
"A000027",
"A001090",
"A001109",
"A001353",
"A001906",
"A004187",
"A004189",
"A004190",
"A004254",
"A006190",
"A010892",
"A018913",
"A049310",
"A049347",
"A056594",
"A057076",
"A075835",
"A101950"
] | null | N. J. A. Sloane | 2025-01-05T19:51:33 | oeisdata/seq/A004/A004190.seq | f2e61ef7f27eebce551ef26f74b6ef3b |
A004191 | Expansion of 1/(1 - 12*x + x^2). | [
"1",
"12",
"143",
"1704",
"20305",
"241956",
"2883167",
"34356048",
"409389409",
"4878316860",
"58130412911",
"692686638072",
"8254109243953",
"98356624289364",
"1172025382228415",
"13965947962451616",
"166419350167190977",
"1983066254043840108",
"23630375698358890319",
"281581442126262843720"
] | [
"nonn",
"easy"
] | 92 | 0 | 2 | [
"A000027",
"A001090",
"A001109",
"A001353",
"A004189",
"A004191",
"A007655",
"A023038",
"A029547",
"A029548",
"A049310",
"A049660",
"A075843",
"A077412",
"A077417",
"A077421",
"A077423",
"A078987",
"A097309",
"A097311",
"A097313",
"A097316",
"A101950",
"A144128",
"A323182"
] | null | N. J. A. Sloane | 2022-12-14T10:55:43 | oeisdata/seq/A004/A004191.seq | d649fa6c5d5c3a7195814f22f5a6981c |
A004192 | Numbers obtained by reversing digits of factorial numbers. | [
"1",
"1",
"2",
"6",
"21",
"27",
"42",
"405",
"2304",
"88263",
"88263",
"861993",
"6100974",
"80207226",
"219287178",
"8634767031",
"88898722902",
"690824786553",
"8275073732046",
"238804001546121",
"466718002092342",
"4490717124909015",
"867067777270004211",
"4667948883761025852",
"48958903334001211551"
] | [
"nonn",
"base"
] | 13 | 0 | 3 | [
"A004153",
"A004192"
] | null | N. J. A. Sloane | 2023-10-25T16:01:10 | oeisdata/seq/A004/A004192.seq | 14ce20a904baee2d11aba9aac9743572 |
A004193 | a(n) = -(-1)^n*2*(2*n+1)!*Bernoulli(2*n)/(n!*2^n). | [
"1",
"1",
"5",
"63",
"1575",
"68409",
"4729725",
"488783295",
"71982456975",
"14550187083705",
"3916321542458325",
"1368981608178405375",
"608576219802039864375",
"337967570725260384533625",
"230885276313275432674678125",
"191452972504088518574149173375",
"190442238700388913304502070009375"
] | [
"nonn",
"nice",
"changed"
] | 40 | 1 | 3 | [
"A000367",
"A002445",
"A004193"
] | null | David W. Cantrell (DWCantrell(AT)sigmaxi.net) | 2025-04-15T05:44:21 | oeisdata/seq/A004/A004193.seq | 716d839caef78a31ef66df437deeb109 |
A004194 | Number of partitions of 1/n into 3 reciprocals of positive integers. | [
"3",
"10",
"21",
"28",
"36",
"57",
"42",
"70",
"79",
"96",
"62",
"160",
"59",
"136",
"196",
"128",
"73",
"211",
"80",
"292",
"245",
"157",
"93",
"366",
"156",
"174",
"230",
"340",
"106",
"497",
"90",
"269",
"322",
"211",
"453",
"538",
"85",
"216",
"378",
"604",
"121",
"623",
"104",
"473",
"648",
"204",
"135",
"706",
"227",
"437",
"387",
"467",
"125",
"601",
"561",
"783",
"385"
] | [
"nonn"
] | 24 | 1 | 1 | [
"A004194",
"A192787",
"A226641",
"A226642",
"A226644",
"A226645",
"A226646",
"A227610"
] | null | Scott Aaronson (philomath(AT)voicenet.com) | 2024-04-11T16:44:54 | oeisdata/seq/A004/A004194.seq | 793fe1ad0e4ea7e0c130c345172d70e3 |
A004195 | The numbers not expressible as the sum of 4 distinct nonzero squares can be written D*4^n union E. This is D. | [
"1",
"2",
"3",
"5",
"6",
"7",
"9",
"10",
"11",
"13",
"14",
"15",
"17",
"18",
"19",
"22",
"23",
"25",
"26",
"27",
"31",
"33",
"34",
"37",
"38",
"42",
"43",
"47",
"55",
"58",
"67",
"73",
"82",
"97",
"103"
] | [
"nonn",
"fini",
"full"
] | 10 | 1 | 2 | [
"A004195",
"A004196",
"A004441"
] | null | N. J. A. Sloane, Dan Hoey | 2014-06-11T17:22:16 | oeisdata/seq/A004/A004195.seq | 25b6bb333d3e1a3adbef45ca977f6f7a |
A004196 | The numbers not expressible as the sum of 4 distinct nonzero squares can be written D*4^n union E. This is E. | [
"21",
"29",
"35",
"41",
"45",
"49",
"53",
"59",
"61",
"69",
"77",
"83",
"89",
"101",
"115",
"157"
] | [
"nonn",
"fini",
"full"
] | 10 | 1 | 1 | [
"A004195",
"A004196",
"A004441"
] | null | N. J. A. Sloane, Dan Hoey | 2014-06-11T17:22:16 | oeisdata/seq/A004/A004196.seq | bcb6c03958ccf9b36aec919d01391134 |
A004197 | Triangle read by rows. T(n, k) = n - k if n - k < k, otherwise k. | [
"0",
"0",
"0",
"0",
"1",
"0",
"0",
"1",
"1",
"0",
"0",
"1",
"2",
"1",
"0",
"0",
"1",
"2",
"2",
"1",
"0",
"0",
"1",
"2",
"3",
"2",
"1",
"0",
"0",
"1",
"2",
"3",
"3",
"2",
"1",
"0",
"0",
"1",
"2",
"3",
"4",
"3",
"2",
"1",
"0",
"0",
"1",
"2",
"3",
"4",
"4",
"3",
"2",
"1",
"0",
"0",
"1",
"2",
"3",
"4",
"5",
"4",
"3",
"2",
"1",
"0",
"0",
"1",
"2",
"3",
"4",
"5",
"5",
"4",
"3",
"2",
"1",
"0",
"0",
"1",
"2",
"3",
"4",
"5",
"6",
"5",
"4",
"3",
"2",
"1",
"0",
"0",
"1",
"2",
"3",
"4",
"5",
"6",
"6",
"5",
"4",
"3",
"2",
"1",
"0",
"0",
"1",
"2"
] | [
"tabl",
"nonn",
"easy",
"nice"
] | 69 | 0 | 13 | [
"A002620",
"A004197",
"A087062",
"A117142",
"A144464",
"A152714",
"A152716",
"A152717",
"A261684"
] | null | David W. Wilson | 2023-05-07T08:28:20 | oeisdata/seq/A004/A004197.seq | 603a2b34380aa7a7dc4f8c39116e0c49 |
A004198 | Table of x AND y, where (x,y) = (0,0),(0,1),(1,0),(0,2),(1,1),(2,0),... | [
"0",
"0",
"0",
"0",
"1",
"0",
"0",
"0",
"0",
"0",
"0",
"1",
"2",
"1",
"0",
"0",
"0",
"2",
"2",
"0",
"0",
"0",
"1",
"0",
"3",
"0",
"1",
"0",
"0",
"0",
"0",
"0",
"0",
"0",
"0",
"0",
"0",
"1",
"2",
"1",
"4",
"1",
"2",
"1",
"0",
"0",
"0",
"2",
"2",
"4",
"4",
"2",
"2",
"0",
"0",
"0",
"1",
"0",
"3",
"4",
"5",
"4",
"3",
"0",
"1",
"0",
"0",
"0",
"0",
"0",
"4",
"4",
"4",
"4",
"0",
"0",
"0",
"0",
"0",
"1",
"2",
"1",
"0",
"5",
"6",
"5",
"0",
"1",
"2",
"1",
"0",
"0",
"0",
"2",
"2",
"0",
"0",
"6",
"6",
"0",
"0",
"2",
"2",
"0",
"0",
"0",
"1",
"0"
] | [
"tabl",
"nonn",
"look"
] | 39 | 0 | 13 | [
"A003986",
"A003987",
"A004198",
"A075173",
"A075175",
"A221146"
] | null | David W. Wilson | 2024-12-28T00:07:29 | oeisdata/seq/A004/A004198.seq | 082c1f8cad961e464eda3bf0e27551d6 |
A004199 | Table of [ x/y ], where (x,y) = (1,1),(1,2),(2,1),(1,3),(2,2),(3,1),... | [
"1",
"0",
"2",
"0",
"1",
"3",
"0",
"0",
"1",
"4",
"0",
"0",
"1",
"2",
"5",
"0",
"0",
"0",
"1",
"2",
"6",
"0",
"0",
"0",
"1",
"1",
"3",
"7",
"0",
"0",
"0",
"0",
"1",
"2",
"3",
"8",
"0",
"0",
"0",
"0",
"1",
"1",
"2",
"4",
"9",
"0",
"0",
"0",
"0",
"0",
"1",
"1",
"2",
"4",
"10",
"0",
"0",
"0",
"0",
"0",
"1",
"1",
"2",
"3",
"5",
"11",
"0",
"0",
"0",
"0",
"0",
"0",
"1",
"1",
"2",
"3",
"5",
"12",
"0",
"0",
"0",
"0",
"0",
"0",
"1",
"1",
"1",
"2",
"3",
"6",
"13",
"0",
"0",
"0",
"0",
"0",
"0",
"0",
"1",
"1",
"2",
"2",
"4",
"6",
"14"
] | [
"tabl",
"nonn"
] | 30 | 1 | 3 | [
"A002541",
"A004199",
"A010766",
"A010783"
] | null | David W. Wilson | 2025-03-19T07:42:03 | oeisdata/seq/A004/A004199.seq | 8936ac2c5fd678760d3eb32ea44ae2bc |
A004200 | Continued fraction for Sum_{k>=0} 1/3^(2^k). | [
"0",
"2",
"5",
"3",
"3",
"1",
"3",
"5",
"3",
"1",
"5",
"3",
"1",
"3",
"3",
"5",
"3",
"1",
"5",
"3",
"3",
"1",
"3",
"5",
"1",
"3",
"5",
"3",
"1",
"3",
"3",
"5",
"3",
"1",
"5",
"3",
"3",
"1",
"3",
"5",
"3",
"1",
"5",
"3",
"1",
"3",
"3",
"5",
"1",
"3",
"5",
"3",
"3",
"1",
"3",
"5",
"1",
"3",
"5",
"3",
"1",
"3",
"3",
"5",
"3",
"1",
"5",
"3",
"3",
"1",
"3",
"5",
"3",
"1",
"5",
"3",
"1",
"3",
"3",
"5",
"3",
"1",
"5",
"3",
"3",
"1",
"3",
"5",
"1",
"3",
"5",
"3",
"1",
"3",
"3",
"5",
"1",
"3",
"5",
"3",
"3",
"1",
"3",
"5",
"3"
] | [
"nonn",
"cofr"
] | 40 | 0 | 2 | [
"A004200",
"A007400",
"A078885"
] | [
"M1312"
] | N. J. A. Sloane | 2022-08-29T13:04:20 | oeisdata/seq/A004/A004200.seq | 538d71d99cb7ff1f8905c7c193d7e2d1 |
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