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.
%I A195594 #16 Aug 17 2024 15:42:20
%S A195594 128,2102,15988,81606,327192,1118398,3419648,9643562,25603228,
%T A195594 64923594,158877948,378088270,879980720,2011806182,4532900488,
%U A195594 10091643138,22244251284,48622120786,105526014500,227633451206,488451508168,1043298475662,2219419264848
%N A195594 Number of ways to place 6n nonattacking kings on a vertical cylinder 12 X 2n.
%C A195594 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).
%H A195594 Ray Chandler, <a href="/A195594/b195594.txt">Table of n, a(n) for n = 1..3296</a>
%H A195594 V. Kotesovec, <a href="https://oeis.org/wiki/User:Vaclav_Kotesovec">Non-attacking chess pieces</a>
%H A195594 <a href="/index/Rec#order_07">Index entries for linear recurrences with constant coefficients</a>, signature (9, -34, 70, -85, 61, -24, 4).
%F A195594 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).
%F A195594 G.f.: -(1 + 119*x + 984*x^2 + 1352*x^3 + 307*x^4 + 9*x^5)/((x-1)^5*(2*x-1)^2).
%F A195594 a(n) = (15839*n - 99729)*2^n + 231/2*n^4 + 1767*n^3 + 26001/2*n^2 + 53295*n + 99730.
%t A195594 LinearRecurrence[{9,-34,70,-85,61,-24,4},{128,2102,15988,81606,327192,1118398,3419648},30] (* _Harvey P. Dale_, Aug 06 2024 *)
%Y A195594 Cf. A194648, A174154, A137432.
%K A195594 nonn
%O A195594 1,1
%A A195594 _Vaclav Kotesovec_, Sep 21 2011