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 A189878 #6 Sep 12 2015 11:00:25 %S A189878 1,0,0,2,10,4,28,20,56,72,200,644,2940,9152,39200,166100,739924, %T A189878 3586840,18640500,107580592,547737844,3080550788 %N A189878 Number of ways to place n nonattacking composite pieces queen + rider[2,5] on an n X n chessboard. %C A189878 a(n) is also number of permutations p of 1,2,...,n satisfying |p(i+2k)-p(i)|<>5k AND |p(j+5k)-p(j)|<>2k AND |p(m+k)-p(m)|<>k for all i>=1, j>=1, m>=1, k>=1, i+2k<=n, j+5k<=n, m+k<=n %H A189878 V. Kotesovec, <a href="https://oeis.org/wiki/User:Vaclav_Kotesovec">Number of ways of placing non-attacking queens, kings, bishops and knights</a> (in English and Czech) %H A189878 Wikipedia, <a href="http://en.wikipedia.org/wiki/Fairy_chess_piece">Fairy chess piece</a> %Y A189878 Cf. A102388, A189875, A189876, A189877, A189856 %K A189878 nonn,hard %O A189878 1,4 %A A189878 _Vaclav Kotesovec_, Apr 29 2011