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 A172223 #18 Feb 16 2025 08:33:11
%S A172223 1,252,1925,6534,20502,57710,142312,308254,606051,1105332,1897899,
%T A172223 3100250,4857000,7344010,10771530,15387310,21479725,29380900,39469835,
%U A172223 52175530,67980110,87421950,111098800,139670910,173864155
%N A172223 Number of ways to place 5 nonattacking zebras on a 5 X n board.
%C A172223 Zebra is a (fairy chess) leaper [2,3].
%H A172223 Vincenzo Librandi, <a href="/A172223/b172223.txt">Table of n, a(n) for n = 1..1000</a>
%H A172223 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 A172223 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/ZebraGraph.html.html">Zebra Graph</a>
%H A172223 Wikipedia, <a href="https://en.wikipedia.org/wiki/Zebra_(chess)">Zebra (chess)</a>
%F A172223 a(n) = 5*(125n^5-1250n^4+7575n^3-28426n^2+64000n-67056)/24, n>=12.
%F A172223 G.f.: x * (14*x^16 -32*x^15 +14*x^14 -292*x^13 +898*x^12 -536*x^11 +514*x^10 -4232*x^9 +7258*x^8 -3296*x^7 +266*x^6 -2018*x^5 +5148*x^4 -1256*x^3 +428*x^2 +246*x +1) / (x-1)^6. - _Vaclav Kotesovec_, Mar 25 2010
%t A172223 CoefficientList[Series[(14 x^16 - 32 x^15 + 14 x^14 - 292 x^13 + 898 x^12 - 536 x^11 + 514 x^10 - 4232 x^9 + 7258 x^8 - 3296 x^7 + 266 x^6 - 2018 x^5 + 5148 x^4 - 1256 x^3 + 428 x^2 + 246 x+1) / (x - 1)^6, {x, 0, 50}], x] (* _Vincenzo Librandi_, May 28 2013 *)
%Y A172223 Cf. A172140, A061991, A172221, A172222.
%K A172223 nonn,easy
%O A172223 1,2
%A A172223 _Vaclav Kotesovec_, Jan 29 2010