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 A189859 #6 Sep 12 2015 11:00:25 %S A189859 1,2,6,24,120,464,2274,13236,91760,740562,5305548,43237840,395858894, %T A189859 4087066620,46633569480,509698057110 %N A189859 Number of ways to place n nonattacking composite pieces rook + rider[3,5] on an n X n chessboard. %C A189859 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 for all i>=1, j>=1, k>=1, i+3k<=n, j+5k<=n %H A189859 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 A189859 Wikipedia, <a href="http://en.wikipedia.org/wiki/Fairy_chess_piece">Fairy chess piece</a> %Y A189859 Cf. A000170, A189852, A189856 %K A189859 nonn,hard %O A189859 1,2 %A A189859 _Vaclav Kotesovec_, Apr 29 2011