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 A172204 #14 Feb 18 2018 14:59:14
%S A172204 0,0,15,194,1974,9856,34475,95466,224589,468854,893646,1585850,
%T A172204 2656976,4246284,6523909,9693986,13997775,19716786,27175904,36746514,
%U A172204 48849626,63959000,82604271,105374074,132919169
%N A172204 Number of ways to place 5 nonattacking kings on a 5 X n board.
%H A172204 Vincenzo Librandi, <a href="/A172204/b172204.txt">Table of n, a(n) for n = 1..1000</a>
%H A172204 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>
%F A172204 a(n) = (625n^5-9750n^4+66415n^3-247626n^2+504664n-446544)/24, n>=4.
%F A172204 G.f.: x^3*(259*x^6-204*x^5+1294*x^4+622*x^3+1035*x^2+104*x+15)/(x-1)^6. - _Vaclav Kotesovec_, Mar 24 2010
%t A172204 CoefficientList[Series[x^2 * (259 * x^6 - 204 * x^5 + 1294 * x^4 + 622 * x^3 + 1035 * x^2 + 104 * x + 15)/(x - 1)^6, {x, 0, 40}], x] (* _Vincenzo Librandi_, May 27 2013 *)
%Y A172204 Cf. A061998, A061991, A172202, A172203.
%K A172204 nonn,easy
%O A172204 1,3
%A A172204 _Vaclav Kotesovec_, Jan 29 2010