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 A195658 #13 Aug 28 2024 13:13:19 %S A195658 1024,50922,815816,7238864,44693472,216134044,877751236,3130270224, %T A195658 10105541204,30179587994,84719304384,226268016376,580363147336, %U A195658 1440139184616,3477556916828,8210011147304,19021962952188,43385173057846,97653259485592,217359166880016 %N A195658 Number of ways to place 9n nonattacking kings on a vertical cylinder 18 X 2n. %C A195658 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) %H A195658 V. Kotesovec, <a href="https://oeis.org/wiki/User:Vaclav_Kotesovec">Non-attacking chess pieces</a> %H A195658 <a href="/index/Rec#order_10">Index entries for linear recurrences with constant coefficients</a>, signature (12, -64, 200, -406, 560, -532, 344, -145, 36, -4). %F A195658 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). %F A195658 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). %F A195658 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. %Y A195658 Cf. A195653, A195648, A137432. %K A195658 nonn %O A195658 1,1 %A A195658 _Vaclav Kotesovec_, Sep 22 2011