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 A189875 #6 Sep 12 2015 11:00:25 %S A189875 1,0,0,2,10,0,0,0,40,52,152,260,1192,4144,18408,71552,312936,1498156, %T A189875 7854672,44923706,213840604,1156549592 %N A189875 Number of ways to place n nonattacking composite pieces queen + rider[1,5] on an n X n chessboard. %C A189875 a(n) is also number of permutations p of 1,2,...,n satisfying |p(i+k)-p(i)|<>5k AND |p(j+5k)-p(j)|<>k AND |p(m+k)-p(m)|<>k for all i>=1, j>=1, m>=1, k>=1, i+k<=n, j+5k<=n, m+k<=n %H A189875 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 A189875 Wikipedia, <a href="http://en.wikipedia.org/wiki/Fairy_chess_piece">Fairy chess piece</a> %Y A189875 Cf. A102388, A189873, A189874, A189852 %K A189875 nonn,hard %O A189875 1,4 %A A189875 _Vaclav Kotesovec_, Apr 29 2011