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 A179403 #15 Aug 05 2024 10:29:56
%S A179403 0,0,0,56,200,486,980,1760,2916,4550,6776,9720,13520,18326,24300,
%T A179403 31616,40460,51030,63536,78200,95256,114950,137540,163296,192500,
%U A179403 225446,262440,303800,349856,400950
%N A179403 Number of ways to place 2 nonattacking kings on an n X n toroidal board.
%H A179403 Vincenzo Librandi, <a href="/A179403/b179403.txt">Table of n, a(n) for n = 1..1000</a>
%H A179403 V. Kotesovec, <a href="https://oeis.org/wiki/User:Vaclav_Kotesovec">Number of ways of placing non-attacking queens and kings on boards of various sizes</a>
%H A179403 <a href="/index/Rec#order_05">Index entries for linear recurrences with constant coefficients</a>, signature (5, -10, 10, -5, 1).
%F A179403 Explicit formula: a(n) = 1/2*n^2*(n-3)*(n+3), n>=3.
%F A179403 G.f.: 2*x^4*(x-2)*(5*x^2 - 13*x + 14)/(x-1)^5.
%t A179403 CoefficientList[Series[2 x^3 (x-2) (5 x^2 - 13 x + 14) / (x - 1)^5, {x, 0, 50}], x] (* _Vincenzo Librandi_, Jun 01 2013 *)
%Y A179403 Cf. A061995.
%K A179403 nonn,easy
%O A179403 1,4
%A A179403 _Vaclav Kotesovec_, Jan 07 2011