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 A194650 #15 Aug 05 2024 10:32:47
%S A194650 0,0,9,68,215,504,1001,1784,2943,4580,6809,9756,13559,18368,24345,
%T A194650 31664,40511,51084,63593,78260,95319,115016,137609,163368,192575,
%U A194650 225524,262521,303884,349943,401040,457529,519776,588159,663068,744905,834084,931031,1036184
%N A194650 Number of ways to place 2 nonattacking kings on an n X n cylindrical chessboard.
%H A194650 V. Kotesovec, <a href="https://oeis.org/wiki/User:Vaclav_Kotesovec">Number of ways of placing non-attacking queens, kings, bishops and knights</a>
%H A194650 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (5, -10, 10, -5, 1).
%F A194650 a(n) = 1/2*n*(n^3 - 9*n + 6), n>=3.
%F A194650 G.f.: x^3*(4*x^4 - 19*x^3 + 35*x^2 - 23*x - 9)/(x-1)^5.
%t A194650 CoefficientList[Series[x^2*(4*x^4 - 19*x^3 + 35*x^2 - 23*x - 9)/(x - 1)^5, {x, 0, 50}], x] (* _Wesley Ivan Hurt_, Dec 27 2023 *)
%Y A194650 Cf. A061995, A179403.
%K A194650 nonn
%O A194650 1,3
%A A194650 _Vaclav Kotesovec_, Aug 31 2011