cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

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A195590 Number of ways to place 2n nonattacking kings on a vertical cylinder 4 X 2n.

Original entry on oeis.org

8, 32, 100, 276, 708, 1732, 4100, 9476, 21508, 48132, 106500, 233476, 507908, 1097732, 2359300, 5046276, 10747908, 22806532, 48234500, 101711876, 213909508, 448790532, 939524100, 1962934276, 4093640708, 8522825732, 17716740100, 36775657476, 76235669508
Offset: 1

Views

Author

Vaclav Kotesovec, Sep 21 2011

Keywords

Comments

Vertical cylinder: a chessboard where it is supposed that the columns 1 and 4 are in contact (number of columns = 4, number of rows = 2n).

Crossrefs

Formula

Recurrence: a(n) = 4*a(n-3) - 8*a(n-2) + 5*a(n-1).
G.f.: -(1+3*x)/((x-1)*(2*x-1)^2).
Explicit formula: a(n) = (5*n-3)*2^n + 4.

A195591 Number of ways to place 3n nonattacking kings on a vertical cylinder 6 X 2n.

Original entry on oeis.org

16, 90, 344, 1082, 3036, 7918, 19648, 47058, 109796, 251126, 565512, 1257754, 2769196, 6046014, 13107536, 28246370, 60555636, 129237382, 274727320, 581960106, 1228931516, 2587886030, 5435818464, 11391730162, 23823647236, 49727668758, 103616086568
Offset: 1

Views

Author

Vaclav Kotesovec, Sep 21 2011

Keywords

Comments

Vertical cylinder: a chessboard where it is supposed that the columns 1 and 6 are in contact (number of columns = 6, number of rows = 2n).

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{6,-13,12,-4},{16,90,344,1082},30] (* Harvey P. Dale, Nov 15 2021 *)

Formula

Recurrence: a(n) = -4*a(n-4) + 12*a(n-3) - 13*a(n-2) + 6*a(n-1).
G.f.: x*(1+10*x+7*x^2)/((x-1)^2*(2*x-1)^2).
a(n) = (31*n - 65)*2^n + 18*n + 66.
E.g.f.: exp(x)*(48*(1 - exp(x)) + x*(18 + 31*exp(x))). - Stefano Spezia, Aug 31 2025

A195592 Number of ways to place 4n nonattacking kings on a vertical cylinder 8 X 2n.

Original entry on oeis.org

32, 256, 1220, 4460, 13932, 39316, 103508, 259372, 626780, 1473764, 3392964, 7682812, 17166476, 37942900, 83115188, 180699980, 390351420, 838619524, 1793087780, 3817890076, 8099228012, 17125372436, 36104600340, 75916936300, 159249370652, 333329766436
Offset: 1

Views

Author

Vaclav Kotesovec, Sep 21 2011

Keywords

Comments

Vertical cylinder: a chessboard where it is supposed that the columns 1 and 8 are in contact (number of columns = 8, number of rows = 2n).

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{7,-19,25,-16,4},{32,256,1220,4460,13932},30] (* Harvey P. Dale, Jan 15 2016 *)

Formula

Recurrence: a(n) = 4*a(n-5) - 16*a(n-4) + 25*a(n-3) - 19*a(n-2) + 7*a(n-1).
G.f.: -(1 + 25*x + 51*x^2 + 11*x^3)/((x-1)^3*(2*x-1)^2).
a(n) = (221*n - 779)*2^n + 44*n^2 + 324*n + 780.

A195593 Number of ways to place 5n nonattacking kings on a vertical cylinder 10 X 2n.

Original entry on oeis.org

64, 732, 4392, 18890, 66532, 205628, 580664, 1536814, 3877300, 9434784, 22327496, 51698178, 117645348, 263992580, 585640568, 1286898262, 2805399156, 6074441896, 13076687560, 28009586346, 59732295204, 126891641612, 268638308152, 566987715710
Offset: 1

Views

Author

Vaclav Kotesovec, Sep 21 2011

Keywords

Comments

Vertical cylinder: a chessboard where it is supposed that the columns 1 and 10 are in contact (number of columns = 10, number of rows = 2n).

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{8, -26, 44, -41, 20, -4}, {64, 732, 4392, 18890, 66532, 205628}, 20] (* Jinyuan Wang, Feb 26 2020 *)

Formula

a(n) = -4*a(n-6) + 20*a(n-5) - 41*a(n-4) + 44*a(n-3) - 26*a(n-2) + 8*a(n-1).
G.f.: (1 + 56*x + 246*x^2 + 156*x^3 + 11*x^4)/((x-1)^4*(2*x-1)^2).
a(n) = (1771*n - 8709)*2^n + 235/3*n^3 + 880*n^2 + 12815/3*n + 8710.

A195594 Number of ways to place 6n nonattacking kings on a vertical cylinder 12 X 2n.

Original entry on oeis.org

128, 2102, 15988, 81606, 327192, 1118398, 3419648, 9643562, 25603228, 64923594, 158877948, 378088270, 879980720, 2011806182, 4532900488, 10091643138, 22244251284, 48622120786, 105526014500, 227633451206, 488451508168, 1043298475662, 2219419264848
Offset: 1

Views

Author

Vaclav Kotesovec, Sep 21 2011

Keywords

Comments

Vertical cylinder: a chessboard where it is supposed that the columns 1 and 12 are in contact (number of columns = 12, number of rows = 2n).

Crossrefs

Programs

  • Mathematica
    LinearRecurrence[{9,-34,70,-85,61,-24,4},{128,2102,15988,81606,327192,1118398,3419648},30] (* Harvey P. Dale, Aug 06 2024 *)

Formula

Recurrence: a(n) = 4*a(n-7) - 24*a(n-6) + 61*a(n-5) - 85*a(n-4) + 70*a(n-3) - 34*a(n-2) + 9*a(n-1).
G.f.: -(1 + 119*x + 984*x^2 + 1352*x^3 + 307*x^4 + 9*x^5)/((x-1)^5*(2*x-1)^2).
a(n) = (15839*n - 99729)*2^n + 231/2*n^4 + 1767*n^3 + 26001/2*n^2 + 53295*n + 99730.

A195595 Number of ways to place 7n nonattacking kings on a vertical cylinder 14 X 2n.

Original entry on oeis.org

256, 6060, 58776, 358564, 1649420, 6286658, 20984924, 63558566, 178909300, 476033636, 1212120160, 2980927200, 7129922604, 16675350430, 38293956836, 86629645122, 193553210580, 427974677968, 938053730248, 2040792091884, 4411561365324, 9483844861978
Offset: 1

Views

Author

Vaclav Kotesovec, Sep 21 2011

Keywords

Comments

Vertical cylinder: a chessboard where it is supposed that the columns 1 and 14 are in contact (number of columns = 14, number of rows = 2n).

Crossrefs

Formula

Recurrence: a(n) = -4*a(n-8) + 28*a(n-7) - 85*a(n-6) + 146*a(n-5) - 155*a(n-4) + 104*a(n-3) - 43*a(n-2) + 10*a(n-1).
G.f.: (1 + 246*x + 3543*x^2 + 9080*x^3 + 4915*x^4 + 442*x^5 + 15*x^6)/((x-1)^6*(2*x-1)^2).
a(n) = (157823*n - 1211433)*2^n + 9121/60*n^5 + 35581/12*n^4 + 352625/12*n^3 + 2179835/12*n^2 + 20456597/30*n + 1211434.

A195652 Number of ways to place 8n nonattacking kings on a 16 X 2n cylindrical chessboard.

Original entry on oeis.org

2304, 9476, 47058, 259372, 1536814, 9643562, 63558566, 437500380, 3130270224, 23174548666, 176740657340, 1382652697282, 11052082053262, 89954475408222, 743275585245898, 6219118726337532, 52583297643941856, 448492643088144992, 3853319870967662784
Offset: 1

Views

Author

Vaclav Kotesovec, Sep 22 2011

Keywords

Comments

This cylinder is horizontal: a chessboard where it is supposed that rows 1 and 2n are in contact (number of columns = 16, number of rows = 2n).

Crossrefs

Formula

Recurrence order is 208.

A195658 Number of ways to place 9n nonattacking kings on a vertical cylinder 18 X 2n.

Original entry on oeis.org

1024, 50922, 815816, 7238864, 44693472, 216134044, 877751236, 3130270224, 10105541204, 30179587994, 84719304384, 226268016376, 580363147336, 1440139184616, 3477556916828, 8210011147304, 19021962952188, 43385173057846, 97653259485592, 217359166880016
Offset: 1

Views

Author

Vaclav Kotesovec, Sep 22 2011

Keywords

Comments

Vertical cylinder: a chessboard where it is supposed that the columns 1 and 18 are in contact (number of columns = 18, number of rows = 2n)

Crossrefs

Formula

Recurrence: a(n) = -4*a(n-10) + 36*a(n-9) - 145*a(n-8) + 344*a(n-7) - 532*a(n-6) + 560*a(n-5) - 406*a(n-4) + 200*a(n-3) - 64*a(n-2) + 12*a(n-1).
G.f.: (1 + 1012*x + 38698*x^2 + 270088*x^3 + 503686*x^4 + 270112*x^5 + 37900*x^6 + 1516*x^7 + 25*x^8)/((x-1)^8*(2*x-1)^2).
a(n) = (21623809*n - 226349399)*2^n + 8913/40*n^7 + 124781/20*n^6 + 376359/4*n^5 + 977074*n^4 + 294753537/40*n^3 + 787733819/20*n^2 + 135269649*n + 226349400.

A195659 Number of ways to place 10n nonattacking kings on a vertical cylinder 20 X 2n.

Original entry on oeis.org

2048, 148352, 3076180, 33175486, 239238888, 1314160492, 5937279840, 23174548666, 80812754568, 257860425672, 766319864440, 2149806985106, 5753007728148, 14807729805472, 36902750545260, 89523360235366, 212335537312668, 494171055510052, 1131839140825580
Offset: 1

Views

Author

Vaclav Kotesovec, Sep 22 2011

Keywords

Comments

Vertical cylinder: a chessboard where it is supposed that the columns 1 and 20 are in contact (number of columns = 20, number of rows = 2n).

Crossrefs

Formula

Recurrence: a(n) = 4*a(n-11) - 40*a(n-10) + 181*a(n-9) - 489*a(n-8) + 876*a(n-7) - 1092*a(n-6) + 966*a(n-5) - 606*a(n-4) + 264*a(n-3) - 76*a(n-2) + 13*a(n-1).
G.f.: -(1 + 2035*x + 121804*x^2 + 1302988*x^3 + 3919832*x^4 + 3822444*x^5 + 1204400*x^6 + 113216*x^7 + 3167*x^8 + 13*x^9)/((x-1)^9*(2*x-1)^2).
a(n) = (296191755*n - 3519976573)*2^n + 524495/2016*n^8 + 4217363/504*n^7 + 2363921/16*n^6 + 66422455/36*n^5 + 557314865/32*n^4 + 8943856601/72*n^3 + 322704776641/504*n^2 + 90034143925/42*n + 3519976574.

A195660 Number of ways to place 11n nonattacking kings on a vertical cylinder 22 X 2n.

Original entry on oeis.org

4096, 433500, 11682296, 153802520, 1301236304, 8155899320, 41180193352, 176740657340, 668845118276, 2290966142762, 7241521734020, 21437333168798, 60123048359816, 161217291701134, 416373921218580, 1041997475699102, 2539265644237492, 6050425313244116
Offset: 1

Views

Author

Vaclav Kotesovec, Sep 22 2011

Keywords

Comments

Vertical cylinder: a chessboard where it is supposed that the columns 1 and 22 are in contact (number of columns = 22, number of rows = 2n).

Crossrefs

Formula

Recurrence: a(n) = -4*a(n-12) + 44*a(n-11) - 221*a(n-10) + 670*a(n-9) - 1365*a(n-8) + 1968*a(n-7) - 2058*a(n-6) + 1572*a(n-5) - 870*a(n-4) + 340*a(n-3) - 89*a(n-2) + 14*a(n-1).
G.f.: (1 + 4082*x + 376245*x^2 + 5977500*x^3 + 27440106*x^4 + 43897316*x^5 + 25742850*x^6 + 5340248*x^7 + 353057*x^8 + 5622*x^9 + 23*x^10)/((x-1)^10*(2*x-1)^2).
a(n) = (4480441703*n - 59644067185)*2^n + 10913705/36288*n^9 + 219791627/20160*n^8 + 6663742261/30240*n^7 + 1542837967/480*n^6 + 314791170001/8640*n^5 + 311982683023/960*n^4 + 6333872421866/2835*n^3 + 56561301500209/5040*n^2 + 46445710897861/1260*n + 59644067186.
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