Datasets:
christopher
/
oeis

Dataset card Data Studio Files
xet
Community
2
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666,262,453B
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1999-12-11 03:00:00
2025-04-28 00:58:08
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29
29
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32
32
A000801
a(n) = Sum_{k = 1..n} floor(2^k / k).
[ "2", "4", "6", "10", "16", "26", "44", "76", "132", "234", "420", "761", "1391", "2561", "4745", "8841", "16551", "31114", "58708", "111136", "211000", "401650", "766372", "1465422", "2807599", "5388709", "10359735", "19946715", "38459505", "74250899", "143524565", "277742293", "538043341", "1043333611", "2025040421" ]
[ "nonn" ]
29
1
1
[ "A000799", "A000801" ]
[ "M1015", "N0381" ]
N. J. A. Sloane
2022-02-01T02:34:57
oeisdata/seq/A000/A000801.seq
e3b93d5cd11f6376ab2586bed2667e6f
A000802
Maximal number of states in the minimal deterministic finite automaton accepting a language over a binary alphabet consisting of some words of length n.
[ "1", "2", "4", "7", "11", "19", "34", "50", "82", "146", "274", "529", "785", "1297", "2321", "4369", "8465", "16657", "33041", "65809", "131344", "196880", "327952", "590096", "1114384", "2162960", "4260112", "8454416", "16843024", "33620240", "67174672", "134283536", "268501264", "536936720", "1073807632", "2147549456", "4295033104" ]
[ "nonn" ]
40
0
2
null
null
Jeffrey Shallit
2024-11-19T11:46:23
oeisdata/seq/A000/A000802.seq
e410b6d1fccb37f322c058bda6c21cab
A000803
a(n+3) = a(n+2) + a(n+1) + a(n) - 4.
[ "0", "0", "8", "4", "8", "16", "24", "44", "80", "144", "264", "484", "888", "1632", "3000", "5516", "10144", "18656", "34312", "63108", "116072", "213488", "392664", "722220", "1328368", "2443248", "4493832", "8265444", "15202520", "27961792", "51429752", "94594060", "173985600", "320009408" ]
[ "nonn", "easy", "nice" ]
38
0
3
[ "A000803", "A000804", "A000805", "A004306" ]
[ "M4472", "N2232" ]
N. J. A. Sloane
2018-09-24T16:53:13
oeisdata/seq/A000/A000803.seq
3054d1ce94ea71841456e92ff7e00e86
A000804
Permanent of a certain cyclic n X n (0,1) matrix.
[ "1", "1", "2", "6", "24", "120", "265", "579", "1265", "2783", "6208", "13909", "31337", "70985", "161545", "369024", "845825", "1944295", "4480285", "10345391", "23930320", "55435605", "128577253", "298529333", "693718721", "1613210120", "3753680073", "8738534315", "20351593033", "47413960239", "110493496000" ]
[ "nonn" ]
38
0
3
[ "A000804", "A000805", "A008305", "A260074" ]
[ "M5375", "N2333" ]
N. J. A. Sloane
2023-06-24T21:48:01
oeisdata/seq/A000/A000804.seq
2de4282f65be49826cb3a428d315a250
A000805
Permanent of a certain cyclic n X n (0,1) matrix.
[ "1", "1", "2", "6", "24", "120", "720", "1854", "4738", "12072", "30818", "79118", "204448", "528950", "1370674", "3557408", "9244418", "24043990", "62573616", "162925614", "424377730", "1105703640", "2881483458", "7510389278", "19577689120", "51038756326", "133066443346", "346944079632", "904622495746", "2358783572710", "6150613767440", "16038217209886" ]
[ "nonn" ]
35
0
3
[ "A000804", "A000805", "A008305" ]
[ "M5471", "N2369" ]
N. J. A. Sloane
2022-09-07T15:44:53
oeisdata/seq/A000/A000805.seq
e8c3cb4ff19917ce0e88ca3ba9ce0c68
A000806
Bessel polynomial y_n(-1).
[ "1", "0", "1", "-5", "36", "-329", "3655", "-47844", "721315", "-12310199", "234615096", "-4939227215", "113836841041", "-2850860253240", "77087063678521", "-2238375706930349", "69466733978519340", "-2294640596998068569", "80381887628910919255", "-2976424482866702081004", "116160936719430292078411" ]
[ "sign", "easy", "nice" ]
131
0
4
[ "A000806", "A001498", "A001515", "A003436", "A101682", "A278990" ]
[ "M3982", "N1651" ]
N. J. A. Sloane
2024-08-14T10:24:48
oeisdata/seq/A000/A000806.seq
20a409c845f03d8a90ef809ac0623bfd
A000807
Quadratic invariants.
[ "1", "2", "14", "182", "3614", "99302", "3554894", "159175382", "8654995454", "558786468422", "42086200603694", "3645412584724022", "358877175474325214", "39758874175808713382", "4915216680878167372814", "673139563824188490513302", "101475126400695241802946494", "16744618803625299734467026182" ]
[ "nonn" ]
34
0
2
[ "A000110", "A000807" ]
[ "M2071", "N0819" ]
N. J. A. Sloane
2020-05-02T07:18:44
oeisdata/seq/A000/A000807.seq
3ed4ee31730ded8d95550959ebdae350
A000808
Number of switching networks (see Harrison reference for precise definition).
[ "10", "76", "8416", "268496896", "576460756464173056", "5316911983139663509773741938679218176", "904625697166532776746648320380374280441295666129685538275829368373028847616" ]
[ "nonn" ]
38
1
1
[ "A000079", "A000808", "A001146" ]
[ "M4726", "N2020" ]
N. J. A. Sloane
2023-12-07T14:52:53
oeisdata/seq/A000/A000808.seq
0d4e2e12258dfaf18f3b90cf949734a9
A000809
Number of switching networks (see Harrison reference for precise definition).
[ "36", "1072", "2100736", "17592201773056", "2475880078571033228681936896", "98079714615416886934934209815610010226578261138395365376" ]
[ "nonn" ]
34
1
1
null
[ "M5258", "N2290" ]
N. J. A. Sloane
2024-01-06T03:59:30
oeisdata/seq/A000/A000809.seq
74ccb4b7488963f5b7003ede1d908107
A000810
Expansion of e.g.f. (sin x + cos x)/cos 3x.
[ "1", "1", "8", "26", "352", "1936", "38528", "297296", "7869952", "78098176", "2583554048", "31336418816", "1243925143552", "17831101321216", "825787662368768", "13658417358350336", "722906928498737152", "13551022195053101056" ]
[ "nonn" ]
37
0
3
[ "A000810", "A007286", "A007289", "A225118" ]
null
N. J. A. Sloane
2020-03-19T16:33:45
oeisdata/seq/A000/A000810.seq
e3ef37c52b5af8d9312180821c4f4ca3
A000811
Number of switching networks (see Harrison reference for precise definition).
[ "16", "160", "13056", "183305216", "153746461690757120", "472614400151965797795362900461748224", "22974620880419880070513913016918297106276186594558904213019777370224066560" ]
[ "nonn" ]
22
1
1
null
[ "M5013", "N2159" ]
N. J. A. Sloane
2022-02-01T01:18:19
oeisdata/seq/A000/A000811.seq
03cd8ee1df6474ed3135368a93442850
A000812
Number of switching networks (see Harrison reference for precise definition).
[ "64", "2304", "2928640", "11745443774464", "660235081293571848291745792", "8718196854704187882046649324045198931057057476097605632" ]
[ "nonn" ]
23
1
1
null
[ "M5334", "N2321" ]
N. J. A. Sloane
2022-02-01T01:18:35
oeisdata/seq/A000/A000812.seq
e0ba355810831998f9ec7e2a3482bf65
A000813
Expansion of (sin x + cos x)/cos 4x.
[ "1", "1", "15", "47", "1185", "6241", "230895", "1704527", "83860545", "796079041", "48942778575", "567864586607", "41893214676705", "574448847467041", "49441928730798255", "782259922208550287", "76946148390480577665", "1379749466246228538241" ]
[ "nonn" ]
25
0
3
[ "A000813", "A001728", "A006873", "A156201", "A156205" ]
null
N. J. A. Sloane
2017-12-30T14:32:21
oeisdata/seq/A000/A000813.seq
0365d5bf1582d79499cfa2a4d1c82c27
A000814
Number of switching networks (see Harrison reference for precise definition).
[ "10", "55", "1996", "11756666", "4805323147589984", "7384600028168436080716029918923776", "179489225628280313255222684940441967551973345417569571214806075240914944" ]
[ "nonn" ]
19
1
1
null
[ "M4714", "N2015" ]
N. J. A. Sloane
2022-02-01T01:18:49
oeisdata/seq/A000/A000814.seq
77b134b9570bbfa5f6c10a49cd5dd9f4
A000815
Number of switching networks (see Harrison reference for precise definition).
[ "36", "666", "384112", "735192450952", "20632358601785638477436416", "136221825854760195018034839832322234167109566010687488" ]
[ "nonn" ]
19
1
1
null
[ "M5254", "N2286" ]
N. J. A. Sloane
2022-02-01T01:19:09
oeisdata/seq/A000/A000815.seq
fbf05218d9a395da5f18c498d1f71420
A000816
E.g.f.: Sum_{n >= 0} a(n) * x^(2*n) / (2*n)! = sin(x)^2 / cos(2*x).
[ "0", "2", "40", "1952", "177280", "25866752", "5535262720", "1633165156352", "635421069967360", "315212388819402752", "194181169538675507200", "145435130631317935357952", "130145345400688287667978240", "137139396592145493713802493952" ]
[ "nonn" ]
62
0
2
[ "A000364", "A000816", "A000819", "A000822", "A000828", "A003707", "A009125", "A009569" ]
null
N. J. A. Sloane
2024-10-18T15:26:08
oeisdata/seq/A000/A000816.seq
32e3f167cedfc509febd3a305b0642e3
A000817
Number of switching networks under action of GL_n(Z_2) acting on 2 variables.
[ "16", "80", "1056", "320416", "1858620869536", "16880173675357998942609488800", "706695723125809149019144715477884710572926078237246360174451424" ]
[ "nonn" ]
24
1
1
null
[ "M5003", "N2153" ]
N. J. A. Sloane
2025-02-01T19:55:12
oeisdata/seq/A000/A000817.seq
43a88dff541f0480993e4ea6c5aedb94
A000818
Number of switching networks under action of GL_n(Z_2) acting on 3 variables.
[ "64", "960", "135040", "14333211520", "7923543700147758911104", "311384101966962110823277061581833720077525851776" ]
[ "nonn" ]
25
1
1
null
[ "M5331", "N2319" ]
N. J. A. Sloane
2025-02-01T19:55:08
oeisdata/seq/A000/A000818.seq
10444bec0cf9796e544a9902a5ba08fc
A000819
E.g.f.: cos(x)^2 / cos(2x) = Sum_{n >= 0} a(n) * x^(2n) / (2n)!.
[ "1", "2", "40", "1952", "177280", "25866752", "5535262720", "1633165156352", "635421069967360", "315212388819402752", "194181169538675507200", "145435130631317935357952", "130145345400688287667978240", "137139396592145493713802493952" ]
[ "nonn" ]
31
0
2
[ "A000364", "A000816", "A000819", "A002436", "A103905" ]
null
N. J. A. Sloane
2017-12-30T14:33:34
oeisdata/seq/A000/A000819.seq
d8a8a5e30469d4de068928d7d8f07e67
A000820
Number of switching networks under action of AG_n(Z_2) acting on 2 variables.
[ "10", "35", "271", "29821", "58561146596", "263752834000960467258171320", "5521060336920386371390128802363265964201729623531400218908632" ]
[ "nonn" ]
24
1
1
null
[ "M4698", "N2007" ]
N. J. A. Sloane
2025-02-01T19:55:04
oeisdata/seq/A000/A000820.seq
f4fe8b83569a282fb767a24360940347
A000821
Number of switching networks under action of AG_n(Z_2) acting on 3 variables.
[ "36", "330", "22060", "920737780", "247617673784972437216", "4865376593267541575898325655326600134256578720" ]
[ "nonn" ]
24
1
1
null
[ "M5253", "N2285" ]
N. J. A. Sloane
2025-02-01T19:55:00
oeisdata/seq/A000/A000821.seq
9bb8170312c34a75c4f58351ab85e785
A000822
Expansion of (sin^2 x + sin x) /cos 2x.
[ "0", "1", "2", "11", "40", "361", "1952", "24611", "177280", "2873041", "25866752", "512343611", "5535262720", "129570724921", "1633165156352", "44110959165011", "635421069967360", "19450718635716001", "315212388819402752", "10784052561125704811" ]
[ "nonn" ]
16
0
3
[ "A000464", "A000816", "A000822" ]
null
N. J. A. Sloane
2022-02-01T01:19:29
oeisdata/seq/A000/A000822.seq
f7b015cab171b74185cdea84749cb67c
A000823
Number of switching networks (see Harrison reference for precise definition).
[ "7", "46", "4336", "134281216", "288230380379570176", "2658455991569831764110243006194384896", "452312848583266388373324160190187140390789016525312000869601987902398529536" ]
[ "nonn" ]
35
1
1
null
[ "M4428", "N1872" ]
N. J. A. Sloane
2023-12-09T12:13:40
oeisdata/seq/A000/A000823.seq
118deace02e3d829f70f80fb70502a99
A000824
Number of switching networks (see Harrison reference for precise definition).
[ "13", "237", "356026", "2932175712336", "412646680050205587085305856", "16346619102569481158480824333166611354489546429742186496" ]
[ "nonn" ]
27
1
1
null
[ "M4917", "N2110" ]
N. J. A. Sloane
2023-12-08T12:06:03
oeisdata/seq/A000/A000824.seq
b0126d1f53f1ed9f02bd9fc767a86524
A000825
Expansion of cos x (1 + sin x ) /cos 2x.
[ "1", "1", "3", "8", "57", "256", "2763", "17408", "250737", "2031616", "36581523", "362283008", "7828053417", "91620376576", "2309644635483", "31191159799808", "898621108880097", "13753735117275136", "445777636063460643", "7625476699018231808" ]
[ "nonn" ]
18
0
3
[ "A000281", "A000825", "A000828", "A000831", "A012393" ]
null
N. J. A. Sloane
2017-12-30T14:44:23
oeisdata/seq/A000/A000825.seq
262145a46369ae283d9cb433077a34d4
A000826
Number of switching networks (see Harrison reference for precise definition).
[ "10", "88", "6616", "91666432", "76873231310808704", "236307200075982899871259747594698752", "11487310440209940035256956508459148560969989043872580978940882909553754112", "166267459448692920381622333807116147427859895760062485070882091322892520958706179582178218311954136674872641052328937320550635171107567787263574147072" ]
[ "nonn" ]
20
1
1
null
[ "M4731", "N2023" ]
N. J. A. Sloane
2015-03-04T20:54:30
oeisdata/seq/A000/A000826.seq
ddd1835d6f6b91d4a7d5f39a86ae4ede
A000827
Number of switching networks (see Harrison reference for precise definition).
[ "20", "484", "497760", "1957701217328", "110039180295740617586514688", "1453032809117364647244136820047121806179196309892169728" ]
[ "nonn" ]
20
1
1
null
[ "M5101", "N2209" ]
N. J. A. Sloane
2015-03-04T21:38:08
oeisdata/seq/A000/A000827.seq
fc696a44f8c9dec5dec6028624611126
A000828
E.g.f. cos(x)/(cos(x) - sin(x)).
[ "1", "1", "2", "8", "40", "256", "1952", "17408", "177280", "2031616", "25866752", "362283008", "5535262720", "91620376576", "1633165156352", "31191159799808", "635421069967360", "13753735117275136", "315212388819402752", "7625476699018231808" ]
[ "nonn", "easy", "changed" ]
108
0
3
[ "A000111", "A000464", "A000825", "A000828", "A185896", "A235131", "A235132" ]
null
N. J. A. Sloane
2025-04-14T07:38:00
oeisdata/seq/A000/A000828.seq
a96e15ecf608c15e36dea8df00b97e65
A000829
Number of switching networks (see Harrison reference for precise definition).
[ "7", "34", "1056", "5884954", "2402661748356256", "3692300014084218317379484106943488", "89744612814140156627611342470220985493433638691231381252948710213328896" ]
[ "nonn" ]
17
1
1
null
[ "M4410", "N1863" ]
N. J. A. Sloane.
2012-03-30T18:39:33
oeisdata/seq/A000/A000829.seq
8d838165f7305c7e17112a865a9acd8e
A000830
Number of switching networks (see Harrison reference for precise definition).
[ "13", "158", "66336", "122544034314", "3438726436264160394888822", "22703637642460032506699838997723739937009913804573344" ]
[ "nonn" ]
19
1
1
null
[ "M4913", "N2106" ]
N. J. A. Sloane
2015-03-04T20:45:07
oeisdata/seq/A000/A000830.seq
aa19c1ff4b5980cee2bc6b5e56ad8ed4
A000831
Expansion of e.g.f. (1 + tan(x))/(1 - tan(x)).
[ "1", "2", "4", "16", "80", "512", "3904", "34816", "354560", "4063232", "51733504", "724566016", "11070525440", "183240753152", "3266330312704", "62382319599616", "1270842139934720", "27507470234550272", "630424777638805504", "15250953398036463616", "388362339077351014400", "10384044045105304174592" ]
[ "nonn" ]
107
0
2
[ "A000111", "A000182", "A000831", "A002436", "A012393", "A155100", "A258880", "A258901", "A258994" ]
null
N. J. A. Sloane
2023-12-02T11:04:24
oeisdata/seq/A000/A000831.seq
9a72296229fef37fcaf71fd17bfd836b
A000832
Number of switching networks (see Harrison reference for precise definition).
[ "10", "46", "556", "160948", "929312039044", "8440086837679170219118159556", "353347861562904574509572357738975845669311200577543225891351084" ]
[ "nonn" ]
20
1
1
null
[ "M4706", "N2011" ]
N. J. A. Sloane
2015-02-12T08:18:02
oeisdata/seq/A000/A000832.seq
02cfd6a7bb5fc04c3cbc357e68715eba
A000833
Number of switching networks (see Harrison reference for precise definition).
[ "20", "220", "23932", "2390065448", "1320590620757744871288", "51897350327827018479313921072100496772300552736" ]
[ "nonn" ]
20
1
1
null
[ "M5093", "N2205" ]
N. J. A. Sloane
2015-02-12T08:18:12
oeisdata/seq/A000/A000833.seq
7d73514016e0f089e44564b62a7a4b5c
A000834
Expansion of exp(x)*(1 + tan(x))/(1 - tan(x)).
[ "1", "3", "9", "35", "177", "1123", "8569", "76355", "777697", "8911683", "113466729", "1589173475", "24280777617", "401898209443", "7163977596889", "136821894075395", "2787312733887937", "60331585563062403", "1382698089425999049" ]
[ "nonn" ]
43
0
2
null
null
N. J. A. Sloane
2025-01-05T19:51:31
oeisdata/seq/A000/A000834.seq
6ab2b924069167d433cc52b5dc73a4a3
A000835
Number of switching networks (see Harrison reference for precise definition).
[ "7", "22", "153", "15209", "29281010032", "131876417000509741750888020", "2760530168460193185695064401186144339478505237725915631330140" ]
[ "nonn" ]
20
1
1
null
[ "M4375", "N1840" ]
N. J. A. Sloane
2015-02-12T08:18:19
oeisdata/seq/A000/A000835.seq
a0aa83bfafd5092e0813283e25769a71
A000836
Number of switching networks (see Harrison reference for precise definition).
[ "13", "87", "4148", "153668757", "41269612629126375351", "810896098877923596128062174904361421866219158" ]
[ "nonn" ]
20
1
1
null
[ "M4905", "N2103" ]
N. J. A. Sloane
2015-02-12T08:18:53
oeisdata/seq/A000/A000836.seq
575682c40ce1a149b30ba5959601e208
A000837
Number of partitions of n into relatively prime parts. Also aperiodic partitions.
[ "1", "1", "1", "2", "3", "6", "7", "14", "17", "27", "34", "55", "63", "100", "119", "167", "209", "296", "347", "489", "582", "775", "945", "1254", "1481", "1951", "2334", "2980", "3580", "4564", "5386", "6841", "8118", "10085", "12012", "14862", "17526", "21636", "25524", "31082", "36694", "44582", "52255", "63260", "74170", "88931", "104302" ]
[ "nonn", "easy", "nice" ]
92
0
4
[ "A000041", "A000740", "A000837", "A007916", "A018783", "A047968", "A055892", "A100953", "A137585", "A168532", "A281116" ]
null
N. J. A. Sloane
2023-07-25T09:50:59
oeisdata/seq/A000/A000837.seq
65625c84c6ea78a97039bad73c5ec670
A000838
Number of n-input 2-output switching networks under action of complementing group on the inputs and outputs.
[ "4", "28", "2272", "67170304", "144115192236605440", "1329227995784915891062320757838184448", "226156424291633194186662080095093570363541849729447858357132587076662853632" ]
[ "easy", "nonn" ]
42
1
1
[ "A000133", "A000838", "A000839" ]
[ "M3629", "N1474" ]
N. J. A. Sloane
2022-02-02T04:51:27
oeisdata/seq/A000/A000838.seq
ac88d6b4e862dd79bf5b9a9c0ce64d98
A000839
Number of n-input 3-output switching networks under action of complementing group on the inputs and outputs.
[ "8", "176", "265728", "2199038984192", "309485009821617747608469504", "12259964326927110866866776295192695943928870296113643520" ]
[ "easy", "nonn" ]
21
1
1
[ "A000133", "A000838", "A000839" ]
[ "M4577", "N1951" ]
N. J. A. Sloane
2022-02-03T02:29:54
oeisdata/seq/A000/A000839.seq
ca2c839ac5cd945a8d4fafd347840671
A000840
Number of cubic bicolored graphs on n unlabeled nodes admitting an automorphism exchanging the colors.
[ "0", "0", "1", "1", "2", "5", "12", "31", "90", "285", "938", "3285", "11983", "45390", "177803", "718390", "2986407", "12749364", "55802982", "250068732", "1145923828", "5363795830", "25620207380", "124767647097", "618983876918", "3126035142910", "16060182735947", "83883575376862", "445164927249466", "2399098651337048" ]
[ "nonn" ]
18
1
5
[ "A000512", "A000840", "A000843", "A004066", "A008325", "A333159" ]
null
Brendan McKay and Eric Rogoyski
2020-03-11T19:01:32
oeisdata/seq/A000/A000840.seq
fc9d6bf3333d71a0433c5197adc8d0a0
A000841
Number of n-input 2-output switching networks under action of symmetric group S(n) on the inputs and complementing group C(2,2) on the outputs.
[ "4", "40", "3264", "45826304", "38436615422689280", "118153600037991449448840725115437056", "5743655220104970017628478254229574276569046648639726053254944342556016640" ]
[ "nonn" ]
17
1
1
[ "A000612", "A000841", "A000842" ]
[ "M3675", "N1498" ]
N. J. A. Sloane
2022-02-01T01:26:47
oeisdata/seq/A000/A000841.seq
1d05dac2459ed6b2088e4150d4d801e6
A000842
Number of n-input 3-output switching networks under action of symmetric group S(n) on the inputs and complementing group C(3,2) on the outputs.
[ "8", "288", "366080", "1468180471808", "82529385161696481036468224", "1089774606838023485255831165505649866382132184512200704" ]
[ "nonn" ]
17
1
1
[ "A000612", "A000841", "A000842" ]
[ "M4582", "N1953" ]
N. J. A. Sloane
2022-02-01T01:27:01
oeisdata/seq/A000/A000842.seq
5029022ef69327d5b4daab483df823ae
A000843
Number of quartic bicolored graphs on n unlabeled nodes admitting an automorphism exchanging the colors.
[ "0", "0", "0", "1", "1", "4", "12", "66", "433", "3442", "30404", "294951", "3093770", "34846185", "419020738", "5355289843", "72466668921", "1034818990771", "15548633703424", "245182764121059", "4047990858838185", "69826392559499108", "1256005988628521464", "23517396850332614602", "457623646061902648705" ]
[ "nonn" ]
20
1
6
[ "A000513", "A000840", "A000843", "A333159" ]
null
Brendan McKay and Eric Rogoyski
2020-03-11T18:00:12
oeisdata/seq/A000/A000843.seq
bab41f532ac74e1c3017d72cd9fe35f3
A000844
Number of switching networks (see Harrison reference for precise definition).
[ "4", "19", "556", "2945786", "1201330980739424", "1846150007042109336331740689419264", "44872306407070078313805671235110493948692333391216774983943586135973888" ]
[ "nonn" ]
23
1
1
null
[ "M3559", "N1441" ]
N. J. A. Sloane
2022-02-01T01:27:16
oeisdata/seq/A000/A000844.seq
16b6f8d8e1c22ebb5b46a497acfdeea6
A000845
Number of switching networks (see Harrison reference for precise definition).
[ "8", "106", "49008", "91901007752", "2579044825238020792325632", "17027728231845024377254356563216673341241082335920128", "7634627316699699128123263912340182782717075954250211317249456247129155629314608610294934410743206996562935808" ]
[ "nonn" ]
23
1
1
null
[ "M4570", "N1947" ]
N. J. A. Sloane
2022-02-01T01:27:29
oeisdata/seq/A000/A000845.seq
d3dae954635c7840f03a90bd573cb8d3
A000846
a(n) = C(3n,n) - C(2n,n).
[ "0", "1", "9", "64", "425", "2751", "17640", "112848", "722601", "4638205", "29860259", "192831288", "1248973544", "8112024844", "52820112480", "344712308064", "2254247833257", "14768735480505", "96917273443305", "636948624057900", "4191706659276675", "27618897144488595", "182181063882796680" ]
[ "nonn", "easy" ]
40
0
3
null
null
Brendan McKay
2024-08-14T10:15:44
oeisdata/seq/A000/A000846.seq
2f1ba65d287bbc8c3d3434f4c07651a5
A000847
Number of n-input 2-output switching networks under action of GL(n,2) on the inputs and complementing group C(2,2) on the outputs.
[ "4", "20", "264", "80104", "464655217384", "4220043418839499735652372200", "176673930781452287254786178869471177643231519559311590043612856" ]
[ "nonn" ]
17
1
1
[ "A000847", "A000848" ]
[ "M3572", "N1448" ]
N. J. A. Sloane
2022-02-02T00:06:01
oeisdata/seq/A000/A000847.seq
632d18315aa343bc9230f2baab87b13d
A000848
Number of n-input 3-output switching networks under action of GL(n,2) on the inputs and complementing group C(3,2) on the outputs.
[ "8", "120", "16880", "1791651440", "990442962518469863888", "38923012745870263852909632697729215009690731472" ]
[ "nonn" ]
18
1
1
[ "A000847", "A000848" ]
[ "M4572", "N1948" ]
N. J. A. Sloane
2022-02-01T01:28:25
oeisdata/seq/A000/A000848.seq
0b33475e12dfc75ae47f94ff6effbad5
A000849
Number of primes <= product of first n primes, A002110(n).
[ "0", "1", "3", "10", "46", "343", "3248", "42331", "646029", "12283531", "300369796", "8028643010", "259488750744", "9414916809095", "362597750396740", "15397728527812858", "742238179058722891", "40068968501510691894", "2251262473052300960826", "139566579945945392719413" ]
[ "nonn", "hard" ]
66
0
3
[ "A000720", "A000849", "A002110", "A003604" ]
null
James D. Ausfahl, gandalf(AT)hrn.office.ssi.net
2020-09-30T03:52:56
oeisdata/seq/A000/A000849.seq
48ac1d63ac02eb22681f679b5a5bf249
A000850
Number of n-input 2-output switching networks under action of AG(n,2) on the inputs and complementing group C(2,2) on the outputs.
[ "4", "11", "79", "7621", "14640634220", "65938208500258353412694720", "1380265084230096592847532200594565116571730065652126434152304" ]
[ "nonn" ]
19
1
1
null
[ "M3427", "N1390" ]
N. J. A. Sloane
2021-12-19T09:49:03
oeisdata/seq/A000/A000850.seq
75d27775b4923930edb5bc9fa229058a
A000851
Number of n-input 3-output switching networks under action of AG(n,2) on the inputs and complementing group C(3,2) on the outputs.
[ "8", "50", "2908", "115125476", "30952209248265753648", "608172074158442696987382009681097839529937904" ]
[ "nonn" ]
21
1
1
null
[ "M4537", "N1925" ]
N. J. A. Sloane
2021-12-19T10:50:36
oeisdata/seq/A000/A000851.seq
90457e53ea34e395fdd9ea10eefc030d
A000852
Numbers beginning with a vowel in English.
[ "1", "8", "11", "18", "80", "81", "82", "83", "84", "85", "86", "87", "88", "89", "100", "101", "102", "103", "104", "105", "106", "107", "108", "109", "110", "111", "112", "113", "114", "115", "116", "117", "118", "119", "120", "121", "122", "123", "124", "125", "126", "127", "128", "129", "130", "131", "132" ]
[ "word", "nonn", "easy" ]
13
1
2
[ "A000852", "A000865", "A000873" ]
null
N. J. A. Sloane
2017-04-01T00:29:28
oeisdata/seq/A000/A000852.seq
dfaf7f773760b1c208b0cfa06aa9c228
A000853
Number of n-input 2-output switching networks under action of complementing group C(2,n) on inputs and S(2) and C(2,2) on outputs.
[ "3", "18", "1200", "33601536", "72057597192044544", "664613997892457950142846397346480128", "113078212145816597093331040047546785266841516594958545044409945396273479680" ]
[ "nonn", "easy" ]
35
1
1
null
[ "M3054", "N1238" ]
N. J. A. Sloane
2022-09-08T08:44:28
oeisdata/seq/A000/A000853.seq
734954a22cecd4981aad0e19e5b6b0eb
A000854
Number of n-input 3-output switching networks under action of complementing group C(2,n) on inputs and S(3) and C(2,3) on outputs.
[ "4", "51", "46218", "366543984720", "51580835042395388382652416", "2043327387821185145142410066588796212566159639921557504" ]
[ "nonn" ]
34
1
1
null
[ "M3687", "N1506" ]
N. J. A. Sloane
2025-01-17T12:09:40
oeisdata/seq/A000/A000854.seq
138e99037cfa314b75badb6dd89760e2
A000855
Final two digits of 2^n.
[ "1", "2", "4", "8", "16", "32", "64", "28", "56", "12", "24", "48", "96", "92", "84", "68", "36", "72", "44", "88", "76", "52", "4", "8", "16", "32", "64", "28", "56", "12", "24", "48", "96", "92", "84", "68", "36", "72", "44", "88", "76", "52", "4", "8", "16", "32", "64", "28", "56", "12", "24", "48", "96", "92", "84", "68", "36", "72", "44", "88", "76", "52", "4", "8", "16", "32", "64", "28" ]
[ "nonn", "base", "easy" ]
34
0
2
[ "A000689", "A000855", "A126605" ]
null
N. J. A. Sloane
2022-07-08T01:57:10
oeisdata/seq/A000/A000855.seq
f77244804d164545b713e12121b18b21
A000856
Number of n-input 2-output switching networks under the action of S(n) on the inputs and S(2) and complementing group C(2,2) on the outputs.
[ "3", "24", "1676", "22920064", "19218307944059712", "59076800018995725211209511239630848", "2871827610052485008814239127114787142200471197616427462842969283498868736" ]
[ "nonn" ]
26
1
1
null
[ "M3108", "N1259" ]
N. J. A. Sloane
2025-01-17T09:45:25
oeisdata/seq/A000/A000856.seq
af52b01bb184dfe6890a1cc3b49190e8
A000857
Number of n-input 3-output switching networks under the action of S(n) on the inputs and S(3) and complementing group C(2,3) on the outputs.
[ "4", "74", "63440", "244728561176", "13754897546985740953546112", "181629101139670580935062344094172140654053010592464896" ]
[ "nonn" ]
24
1
1
null
[ "M3696", "N1511" ]
N. J. A. Sloane
2020-01-13T13:54:57
oeisdata/seq/A000/A000857.seq
c52917b522856d3ed1160ffee72e09c9
A000858
Duplicate of A003436.
[ "0", "1", "4", "31", "293", "3326", "44189", "673471", "11588884", "222304897", "4704612119" ]
[ "dead" ]
5
1
3
null
null
null
2007-05-11T03:00:00
oeisdata/seq/A000/A000858.seq
e18cd6daae57a6b8649c487ec16716fe
A000859
Number of n-input 2-output switching networks under action of S(n) and complementing group C(2,2) on inputs and outputs.
[ "3", "13", "308", "1476218", "600665577652576", "923075003521054806676605033098240", "22436153203535039156902835617555247833069649686831685624592283895635968" ]
[ "nonn" ]
19
1
1
null
[ "M2963", "N1198" ]
N. J. A. Sloane
2017-04-01T00:31:04
oeisdata/seq/A000/A000859.seq
fea62888b99f850e9466b4fa17ca1d42
A000860
Number of n-input 3-output switching networks under action of S(n) and complementing group C(2,3) on inputs and outputs.
[ "4", "34", "8900", "15320103918", "429840804866758538021686", "2837954705307504063799234409931200916180905873402528" ]
[ "nonn" ]
19
1
1
null
[ "M3656", "N1488" ]
N. J. A. Sloane
2017-04-01T00:31:23
oeisdata/seq/A000/A000860.seq
6e60cd823fe718cd48010d7c1d1e5fe6
A000861
Numbers ending with a vowel in American English.
[ "0", "1", "2", "3", "5", "9", "12", "21", "22", "23", "25", "29", "31", "32", "33", "35", "39", "41", "42", "43", "45", "49", "51", "52", "53", "55", "59", "61", "62", "63", "65", "69", "71", "72", "73", "75", "79", "81", "82", "83", "85", "89", "91", "92", "93", "95", "99", "101", "102", "103", "105", "109", "112", "121", "122", "123", "125", "129", "131", "132", "133", "135", "139", "141", "142" ]
[ "word", "nonn", "easy" ]
36
1
3
[ "A000861", "A059437", "A152592", "A247359", "A247360", "A247361" ]
null
N. J. A. Sloane
2024-04-19T01:58:47
oeisdata/seq/A000/A000861.seq
6424f0b9c80d74c4bc61da43bbaa709c
A000862
Number of n-input 2-output switching networks under action of AG(n,2) and complementing group C(2,2) on inputs and outputs.
[ "3", "8", "49", "3963", "7320535610", "32969104250143930769244222", "690132542115048296423766100299538236974685246850905568050026" ]
[ "nonn" ]
19
1
1
null
[ "M2765", "N1112" ]
N. J. A. Sloane
2017-04-01T00:32:33
oeisdata/seq/A000/A000862.seq
97c59d1c45f404ffda10a18077feaa19
A000863
Number of n-input 3-output switching networks under action of AG(n,2) and complementing group C(2,3) on inputs and outputs.
[ "4", "19", "632", "19245637", "5158701627878530987", "101362012359740449534162019620212891642247346" ]
[ "nonn" ]
28
1
1
null
[ "M3560", "N1442" ]
N. J. A. Sloane
2025-01-17T10:47:36
oeisdata/seq/A000/A000863.seq
586f8a583762a4496cd62400ffd584a4
A000864
Deceptive nonprimes: composite numbers k that divide the repunit R_{k-1}.
[ "91", "259", "451", "481", "703", "1729", "2821", "2981", "3367", "4141", "4187", "5461", "6533", "6541", "6601", "7471", "7777", "8149", "8401", "8911", "10001", "11111", "12403", "13981", "14701", "14911", "15211", "15841", "19201", "21931", "22321", "24013", "24661", "27613", "29341", "34133" ]
[ "nonn" ]
34
1
1
[ "A000864", "A002275", "A005939" ]
null
Tim Ray (c268scm(AT)semovm.semo.edu)
2021-08-14T18:52:29
oeisdata/seq/A000/A000864.seq
8eef84d5a1de609da9b5203f95ecba6b
A000865
Numbers beginning with letter 'o' in English.
[ "1", "100", "101", "102", "103", "104", "105", "106", "107", "108", "109", "110", "111", "112", "113", "114", "115", "116", "117", "118", "119", "120", "121", "122", "123", "124", "125", "126", "127", "128", "129", "130", "131", "132", "133", "134", "135" ]
[ "word", "nonn" ]
23
1
2
[ "A000852", "A000865", "A131835" ]
null
N. J. A. Sloane
2023-12-11T14:16:09
oeisdata/seq/A000/A000865.seq
0b3ff7632489e67c821381e77df40c1d
A000866
2^n written in base 5.
[ "1", "2", "4", "13", "31", "112", "224", "1003", "2011", "4022", "13044", "31143", "112341", "230232", "1011014", "2022033", "4044121", "13143242", "31342034", "113234123", "232023301", "1014102102", "2033204204", "4121413413", "13243332331", "32042220212", "114134440424", "233324431403", "1022204413311" ]
[ "nonn", "base", "easy" ]
12
0
2
[ "A000079", "A000244", "A000866", "A004642", "A004655", "A004656", "A004658", "A004659" ]
null
N. J. A. Sloane, Jacques Haubrich (jhaubrich(AT)freeler.nl)
2018-06-23T09:13:02
oeisdata/seq/A000/A000866.seq
70ba27ee8f39805423f540f1fdbaf54a
A000867
Numbers beginning with letter 'f' in English.
[ "4", "5", "14", "15", "40", "41", "42", "43", "44", "45", "46", "47", "48", "49", "50", "51", "52", "53", "54", "55", "56", "57", "58", "59", "400", "401", "402", "403", "404", "405", "406", "407", "408", "409", "410", "411", "412", "413", "414", "415", "416", "417", "418", "419", "420", "421", "422", "423", "424", "425", "426", "427", "428", "429", "430", "431", "432" ]
[ "word", "nonn" ]
29
1
1
[ "A000865", "A000867", "A000870", "A000873", "A000981", "A006092", "A125299" ]
null
N. J. A. Sloane
2023-12-12T22:36:46
oeisdata/seq/A000/A000867.seq
44ba97888e458822c7e9dc7a604942ff
A000868
Number of switching networks with C(2,n) acting on domain and GL(2,Z2) acting on range.
[ "4", "21", "1531", "44782251", "96076794891512491", "886151997189943927518995693301312171", "150770949527755462791108053396729046910357127815416821444325531778055580331" ]
[ "nonn" ]
25
1
1
null
[ "M3580", "N1451" ]
N. J. A. Sloane
2015-02-12T08:45:54
oeisdata/seq/A000/A000868.seq
4db901860077648806d80f78cab062db
A000869
Number of switching networks with C(2,n) acting on domain and GL(3,Z2) acting on range.
[ "4", "27", "14056", "104751025086", "14737381492157353997140846", "583807825091767184801127161305581049499763751729421166" ]
[ "nonn", "easy" ]
29
1
1
null
[ "M3620", "N1470" ]
N. J. A. Sloane
2022-09-08T08:44:28
oeisdata/seq/A000/A000869.seq
7ab3abeb46adc0891306c5f7c80cc675
A000870
Numbers beginning with letter 's' in English.
[ "6", "7", "16", "17", "60", "61", "62", "63", "64", "65", "66", "67", "68", "69", "70", "71", "72", "73", "74", "75", "76", "77", "78", "79", "600", "601", "602", "603", "604", "605", "606", "607", "608", "609", "610", "611", "612", "613", "614", "615", "616", "617", "618", "619", "620" ]
[ "word", "nonn" ]
13
1
1
[ "A000865", "A000867", "A000870", "A000873", "A000981", "A006092", "A125299" ]
null
N. J. A. Sloane
2017-04-01T00:33:28
oeisdata/seq/A000/A000870.seq
f64239dbe0e6c97df669d5c9a689cc2f
A000871
Number of switching networks with S(n) acting on the domain and GL(2,2) acting on the range.
[ "5", "35", "2266", "30564722", "25624410747226866", "78769066691994300606138801216143967", "3829103480069980011752318836153049525544593512352968628868212239132475999" ]
[ "nonn" ]
19
1
1
null
[ "M3981", "N1650" ]
N. J. A. Sloane
2017-04-01T00:33:45
oeisdata/seq/A000/A000871.seq
b80ca4295134df3799168e0aa9ce6e67
A000872
Number of switching networks with S(n) acting on the domain and GL(3,2) acting on the range.
[ "5", "46", "19930", "69945183326", "3929970742021874526325166", "51894028897048737452225300581594776441516899880213358" ]
[ "nonn" ]
18
1
1
null
[ "M4002", "N1658" ]
N. J. A. Sloane
2017-04-01T00:34:02
oeisdata/seq/A000/A000872.seq
c1e8e4e2fd4eccf27730bfebd0d4c775
A000873
Numbers beginning with letter 'e' in English.
[ "8", "11", "18", "80", "81", "82", "83", "84", "85", "86", "87", "88", "89", "800", "801", "802", "803", "804", "805", "806", "807", "808", "809", "810", "811", "812", "813", "814", "815", "816", "817", "818", "819", "820", "821", "822", "823", "824", "825", "826", "827", "828", "829" ]
[ "word", "nonn" ]
19
1
1
[ "A000852", "A000865", "A000867", "A000870", "A000873", "A000981", "A006092" ]
null
N. J. A. Sloane
2017-04-01T00:34:16
oeisdata/seq/A000/A000873.seq
93534b8935170e3eef8070923e9769c5
A000874
Number of switching networks with S(n) and C(2,2) acting on the domain and GL(2,2) acting on the range.
[ "4", "16", "392", "1966074", "800887365826790", "1230766671361406290474145896188319", "29914870938046718875870447490073662976109190218710989290080175747776895" ]
[ "nonn" ]
20
1
1
null
[ "M3533", "N1433" ]
N. J. A. Sloane
2017-04-01T00:24:21
oeisdata/seq/A000/A000874.seq
42f4040a1bc39b42b1f2f7be5361981e
A000875
Number of switching networks with S(n) and C(2,2) acting on the domain and GL(3,2) acting on the range.
[ "4", "21", "2914", "4379140552", "122811659002267408721700", "810844201516429733173715469705141125645071310611982" ]
[ "nonn" ]
20
1
1
null
[ "M3581", "N1452" ]
N. J. A. Sloane
2017-04-01T00:24:43
oeisdata/seq/A000/A000875.seq
5ef2eafb97d92407d48e53648dc10658
A000876
From a self-replicating tiling.
[ "1", "1", "0", "0", "3", "3", "0", "0", "1", "0", "1", "1", "2", "0", "7", "7", "0", "2", "1", "1", "0", "1", "2", "2", "3", "0", "3", "6", "10", "0", "13", "2", "9", "3", "10", "0", "15", "15", "0", "10", "3", "9", "2", "13", "0", "10", "6", "3", "0", "3", "2", "2", "5", "2", "25", "1", "42", "12", "7", "0", "7", "28", "170", "1", "217", "10", "37", "1" ]
[ "nonn" ]
21
0
5
[ "A000360", "A000361", "A000876" ]
null
M. Jeremie Lafitte (Levitas)
2017-04-20T12:09:44
oeisdata/seq/A000/A000876.seq
3aa8e2dc13aadf08574e4838c561bef3
A000877
Number of switching networks with GL(n,2) acting on the domain and GL(2,2) acting on the range.
[ "5", "20", "206", "54155", "309771751363", "2813362279226503905263636259", "117782620520968191503190785913014275478335890027037842956986579" ]
[ "nonn" ]
20
1
1
null
[ "M3910", "N1605" ]
N. J. A. Sloane
2017-04-01T00:22:47
oeisdata/seq/A000/A000877.seq
aad31775b5e0c786c8ecf8d86d73d5f1
A000878
Number of switching networks with GL(n,2) acting on the domain and GL(3,2) acting on the range.
[ "5", "27", "1204", "85617952", "47163951612740818544", "1853476797422393518997156640106964554652232210", "1431405317608062035603436602561550164804819376613495652537557566563513965206452741153347013992258358" ]
[ "nonn" ]
23
1
1
null
[ "M3948", "N1627" ]
N. J. A. Sloane
2025-02-01T19:55:17
oeisdata/seq/A000/A000878.seq
96f5c360d487c1dea98cb013ef86e103
A000879
Number of primes < prime(n)^2.
[ "2", "4", "9", "15", "30", "39", "61", "72", "99", "146", "162", "219", "263", "283", "329", "409", "487", "519", "609", "675", "705", "811", "886", "1000", "1163", "1252", "1294", "1381", "1423", "1523", "1877", "1976", "2141", "2190", "2489", "2547", "2729", "2915", "3043", "3241", "3436", "3512", "3868", "3945", "4089", "4164", "4627", "5106" ]
[ "nonn" ]
50
1
1
[ "A000720", "A000879", "A000885", "A001248", "A050216", "A052180", "A054270", "A089609" ]
null
gandalf(AT)hrn.office.ssi.net (James D. Ausfahl)
2024-04-21T23:01:19
oeisdata/seq/A000/A000879.seq
029cec572efc1be2429cd104906d0daa
A000880
Number of switching networks with AG(n,2) acting on the domain and GL(2,2) acting on the range.
[ "4", "11", "64", "5276", "9760628902", "43958805666856252758341426", "920176722820064395231688133731722351411281463557094398071921" ]
[ "nonn" ]
19
1
1
null
[ "M3425", "N1389" ]
N. J. A. Sloane
2017-04-01T00:23:21
oeisdata/seq/A000/A000880.seq
be0cc411bb2f06578814c42a5b98fd0d
A000881
Number of switching networks with AG(n,2) acting on the domain and GL(3,2) acting on the range.
[ "4", "15", "276", "5534533", "1473914807822315239", "28960574959925842749932484608400325311784104", "11182854043812984653151849586832952714557996202582672732591909323787317314909793862964567968430394" ]
[ "nonn" ]
19
1
1
null
[ "M3508", "N1425" ]
N. J. A. Sloane
2017-04-01T00:34:35
oeisdata/seq/A000/A000881.seq
624b930fde4b69452787f8db7f925e37
A000882
Number of twin prime pairs <= product of first n primes.
[ "0", "1", "4", "15", "69", "468", "4636", "57453", "896062", "18463713", "425177757", "11997649372", "385088898632", "13280323588034", "509456736126003" ]
[ "nonn", "more", "hard" ]
18
1
3
[ "A000849", "A000882", "A002110" ]
null
gandalf(AT)hrn.office.ssi.net (James D. Ausfahl)
2022-01-26T06:23:06
oeisdata/seq/A000/A000882.seq
ff2d7ef436c763f118d3605b46038637
A000883
Number of switching networks with C(2,n) acting on the domain and AG(2,2) acting on the range.
[ "2", "9", "443", "11211435", "24019199779842731", "221537999297485986455406144733751979", "37692737381938865697777013349182261812327566685142592258699083037385861803" ]
[ "nonn", "easy" ]
34
1
1
null
[ "M1956", "N0774" ]
N. J. A. Sloane
2022-09-08T08:44:28
oeisdata/seq/A000/A000883.seq
a35eeed3d9dea6c15cdbd0f44ef8fa20
A000884
Number of switching networks with C(2,n) acting on the domain and AG(3,2) acting on the domain.
[ "2", "10", "2104", "13098898366", "1842172695541070949024622", "72975978136470898183217648961745628914523492408810350" ]
[ "nonn", "easy" ]
25
1
1
null
[ "M1994", "N0786" ]
N. J. A. Sloane
2017-04-01T00:36:17
oeisdata/seq/A000/A000884.seq
49ee8872aa7561034db0a3b1f818b10e
A000885
Number of twin prime pairs < square of n-th prime.
[ "0", "2", "4", "6", "10", "12", "19", "21", "25", "33", "35", "46", "53", "56", "67", "80", "93", "98", "117", "128", "131", "146", "160", "174", "195", "210", "217", "227", "233", "244", "286", "298", "325", "331", "376", "386", "406", "423", "444", "467", "492", "505", "554", "561", "581", "589", "641", "700", "723", "732", "748", "780", "789", "835", "868", "895", "938", "945", "975" ]
[ "nonn" ]
14
1
2
[ "A000879", "A000885" ]
null
gandalf(AT)hrn.office.ssi.net (James D. Ausfahl)
2013-11-21T12:45:45
oeisdata/seq/A000/A000885.seq
985ff7a9be9333e42eefc9f64b00d72a
A000886
Number of switching networks with S(n,2) acting on the domain and AG(2,2) acting on the range where S(n,k) is the symmetric group acting on k variables.
[ "2", "11", "590", "7644658", "6406102803167154", "19692266672998575394929289976513119", "957275870017495002938079709038262383344122314736541166025242955633607263" ]
[ "nonn" ]
23
1
1
null
[ "M2012", "N0795" ]
N. J. A. Sloane
2025-02-01T19:55:29
oeisdata/seq/A000/A000886.seq
d40ede4d5bf7b381020dc9b6cb654a4c
A000887
Number of switching networks with S(n,2) acting on the domain and AG(3,2) acting on the range where S(n,k) is the symmetric group acting on k variables.
[ "2", "12", "2828", "8747130342", "491246345257275414284942", "6486753612131092188914472969769826152814897906580334" ]
[ "nonn" ]
23
1
1
null
[ "M2054", "N0813" ]
N. J. A. Sloane
2025-02-01T19:55:23
oeisdata/seq/A000/A000887.seq
d3cc9bf61bb85c3d50ef6cb5217edbf0
A000888
a(n) = (2*n)!^2 / ((n+1)!*n!^3).
[ "1", "2", "12", "100", "980", "10584", "121968", "1472328", "18404100", "236390440", "3103161776", "41469525552", "562496897872", "7726605740000", "107289439704000", "1503840313184400", "21252802073091300", "302539888334593800", "4334635827016110000", "62464383654579522000", "904841214653480504400" ]
[ "nonn", "easy" ]
135
0
2
[ "A000108", "A000888", "A002894", "A088538", "A089835", "A125558" ]
null
N. J. A. Sloane
2023-10-02T20:15:55
oeisdata/seq/A000/A000888.seq
24e45c71c94b8ef9e252b6156ced5b4c
A000889
Number of switching networks with S(n) and C(2,2) acting on the domain and AG(2,2) acting on the range.
[ "2", "7", "124", "494298", "200221917406630", "307691667840351694566029898844575", "7478717734511679718967611872518416516838871889762225738677912465064319" ]
[ "nonn" ]
22
1
1
null
[ "M1819", "N0722" ]
N. J. A. Sloane
2017-04-01T00:19:44
oeisdata/seq/A000/A000889.seq
93fec564e0151c3574736d312feb7ad9
A000890
Number of switching networks with S(n) and C(2,2) acting on the domain and AG(2,3) acting on the range.
[ "2", "8", "502", "547849868", "15351457458188948591044", "101355525189553716762153010939347719113626111895054", "45444210218450590048352761382977278474163061892945988503535816179384800906003492121663432508203634748567436" ]
[ "nonn" ]
20
1
1
null
[ "M1908", "N0753" ]
N. J. A. Sloane
2017-04-01T00:20:09
oeisdata/seq/A000/A000890.seq
2547e2aab02a9b126e5d116e7454ccd8
A000891
a(n) = (2*n)!*(2*n+1)! / (n! * (n+1)!)^2.
[ "1", "3", "20", "175", "1764", "19404", "226512", "2760615", "34763300", "449141836", "5924217936", "79483257308", "1081724803600", "14901311070000", "207426250094400", "2913690606794775", "41255439318353700", "588272005095043500" ]
[ "nonn", "changed" ]
156
0
2
[ "A000108", "A000142", "A000356", "A000891", "A000894", "A001263", "A010370", "A038535", "A065097", "A080936", "A090181", "A145600", "A145601", "A145602", "A145603", "A185650", "A248045", "A267981", "A358371", "A358579", "A358586", "A358590" ]
null
N. J. A. Sloane
2025-04-24T10:46:20
oeisdata/seq/A000/A000891.seq
04372c25ddcf6aa6d3b982f2a7d4c37b
A000892
Number of switching networks with GL(n,2) acting on the domain and AG(2,2) acting on the range.
[ "2", "7", "60", "13733", "77443340533", "703340569806668663530742581", "29445655130242047875797696478261941465296049517922025033117465" ]
[ "nonn" ]
24
1
1
null
[ "M1815", "N0719" ]
N. J. A. Sloane
2017-04-01T01:01:49
oeisdata/seq/A000/A000892.seq
be12e48828bbcfd723b5eb809f13fb34
A000893
Number of switching networks with GL(n,2) acting on the domain and AG(3,2) acting on the range.
[ "2", "8", "214", "10740500", "5895494078673763322", "231684599677799190148636584446502265460151192" ]
[ "nonn" ]
24
1
1
null
[ "M1906", "N0752" ]
N. J. A. Sloane
2017-04-01T00:20:38
oeisdata/seq/A000/A000893.seq
2d9a342b3c11f788c3d505e5bd14daa5
A000894
a(n) = (2*n)!*(2*n+1)! /((n+1)! *n!^3).
[ "1", "6", "60", "700", "8820", "116424", "1585584", "22084920", "312869700", "4491418360", "65166397296", "953799087696", "14062422446800", "208618354980000", "3111393751416000", "46619049708716400", "701342468412012900" ]
[ "nonn", "easy" ]
64
0
2
[ "A000108", "A000142", "A000217", "A000891", "A000894", "A000984", "A001700", "A002463", "A002894", "A082578", "A103371", "A132813", "A241530", "A248845" ]
null
N. J. A. Sloane
2025-03-12T08:06:32
oeisdata/seq/A000/A000894.seq
4f6f71b3b4a3b330cb0d1ab12fa1bfae
A000895
Number of switching networks with AG(n,2) acting on the domain and AG(2,2) acting on the range.
[ "2", "5", "24", "1430", "2440325272", "10989701416724479725189828", "230044180705016098807922033434683198117461325308508929710583" ]
[ "nonn" ]
18
1
1
null
[ "M1543" ]
N. J. A. Sloane
2017-04-01T00:37:18
oeisdata/seq/A000/A000895.seq
b8e866cb284cf94db448414a337948e5
A000896
Number of switching networks with AG(n,2) acting on the domain and AG(3,2) acting on the range.
[ "2", "6", "70", "700229", "184239362390740969", "3620071869990730348276861702715495626355546", "1397856755476623081643981198354119089406016417825924278115794483751825503676804770385912700712220" ]
[ "nonn" ]
21
1
1
null
[ "M1720", "N0682" ]
N. J. A. Sloane
2017-04-01T00:37:35
oeisdata/seq/A000/A000896.seq
e032dbe8621fdd70dbc77f37a0616161
A000897
a(n) = (4*n)! / ((2*n)!*n!^2).
[ "1", "12", "420", "18480", "900900", "46558512", "2498640144", "137680171200", "7735904619300", "441233078286000", "25467973278667920", "1484298740174927040", "87202550985276963600", "5157850293780050462400", "306839461354466267304000", "18344908596179023234548480" ]
[ "nonn", "easy", "changed" ]
129
0
2
[ "A000897", "A000984", "A001448", "A002894", "A002897", "A005809", "A005810", "A006480", "A008977", "A113424", "A186420", "A188662" ]
null
N. J. A. Sloane
2025-04-18T22:27:17
oeisdata/seq/A000/A000897.seq
cc808f06e2d9950a2901a1e1e5b8b6c2
A000898
a(n) = 2*(a(n-1) + (n-1)*a(n-2)) for n >= 2 with a(0) = 1.
[ "1", "2", "6", "20", "76", "312", "1384", "6512", "32400", "168992", "921184", "5222208", "30710464", "186753920", "1171979904", "7573069568", "50305536256", "342949298688", "2396286830080", "17138748412928", "125336396368896", "936222729254912", "7136574106003456", "55466948299223040", "439216305474605056", "3540846129311916032" ]
[ "nonn", "easy", "nice" ]
181
0
2
[ "A000085", "A000712", "A000898", "A004003", "A066051", "A099390", "A100861", "A122832", "A135401", "A138178", "A153452", "A185296", "A294042", "A297388", "A299699", "A299926", "A300056", "A300060", "A376826" ]
[ "M1648", "N0645" ]
N. J. A. Sloane
2025-03-15T05:27:27
oeisdata/seq/A000/A000898.seq
221a0d90d1144b464019dc3285828877
A000899
Number of solutions to the rook problem on an n X n board having a certain symmetry group (see Robinson for details).
[ "0", "0", "0", "1", "9", "70", "571", "4820", "44676", "450824", "4980274", "59834748", "778230060", "10896609768", "163456629604", "2615335902176", "44460874280032", "800296440705472", "15205636325496568", "304112744618157872", "6386367741011250672" ]
[ "nonn", "nice", "easy" ]
32
1
5
[ "A000899", "A000900" ]
[ "M4645", "N1987" ]
N. J. A. Sloane
2018-01-10T16:04:50
oeisdata/seq/A000/A000899.seq
8c55d6d051019f1921f82832d105ddf2
A000900
Number of solutions to the rook problem on an n X n board having a certain symmetry group (see Robinson for details).
[ "0", "0", "0", "1", "2", "10", "28", "106", "344", "1272", "4592", "17692", "69384", "283560", "1191984", "5171512", "23087168", "105883456", "498572416", "2404766224", "11878871456", "59975885856", "309439708352", "1628919330208", "8746079933568", "47840206525056" ]
[ "nonn", "easy", "nice" ]
32
0
5
null
[ "M1964", "N0777" ]
N. J. A. Sloane
2018-01-10T16:04:59
oeisdata/seq/A000/A000900.seq
dcfdb0a6b9fcbe157177e07a7a6bf8e6