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 A195659 #13 Aug 28 2024 13:14:58 %S A195659 2048,148352,3076180,33175486,239238888,1314160492,5937279840, %T A195659 23174548666,80812754568,257860425672,766319864440,2149806985106, %U A195659 5753007728148,14807729805472,36902750545260,89523360235366,212335537312668,494171055510052,1131839140825580 %N A195659 Number of ways to place 10n nonattacking kings on a vertical cylinder 20 X 2n. %C A195659 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). %H A195659 V. Kotesovec, <a href="https://oeis.org/wiki/User:Vaclav_Kotesovec">Non-attacking chess pieces</a> %H A195659 <a href="/index/Rec#order_11">Index entries for linear recurrences with constant coefficients</a>, signature (13, -76, 264, -606, 966, -1092, 876, -489, 181, -40, 4). %F A195659 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). %F A195659 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). %F A195659 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. %Y A195659 Cf. A195654, A195649, A137432. %K A195659 nonn %O A195659 1,1 %A A195659 _Vaclav Kotesovec_, Sep 22 2011