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 A189880 #6 Sep 12 2015 11:00:25 %S A189880 1,0,0,2,10,0,8,24,72,116,336,1124,4056,12628,58984,263066,1124116, %T A189880 5388972,29219680,173696136,967249940 %N A189880 Number of ways to place n nonattacking composite pieces queen + rider[3,5] on an n X n chessboard. %C A189880 a(n) is also number of permutations p of 1,2,...,n satisfying |p(i+3k)-p(i)|<>5k AND |p(j+5k)-p(j)|<>3k AND |p(m+k)-p(m)|<>k for all i>=1, j>=1, m>=1, k>=1, i+3k<=n, j+5k<=n, m+k<=n %H A189880 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 A189880 Wikipedia, <a href="http://en.wikipedia.org/wiki/Fairy_chess_piece">Fairy chess piece</a> %Y A189880 Cf. A102388, A189875, A189878, A189859, A189879 %K A189880 nonn,hard %O A189880 1,4 %A A189880 _Vaclav Kotesovec_, Apr 29 2011