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 A189853 #6 Sep 12 2015 11:00:25 %S A189853 1,2,6,24,120,720,2640,13596,87768,680274,6090756,61678252,482005340, %T A189853 4454053680,46705656280,549750105234 %N A189853 Number of ways to place n nonattacking composite pieces rook + rider[1,6] on an n X n chessboard. %C A189853 a(n) is also number of permutations p of 1,2,...,n satisfying |p(i+k)-p(i)|<>6k AND |p(j+6k)-p(j)|<>k for all i>=1, j>=1, k>=1, i+k<=n, j+6k<=n %H A189853 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 A189853 Wikipedia, <a href="http://en.wikipedia.org/wiki/Fairy_chess_piece">Fairy chess piece</a> %Y A189853 Cf. A000170, A189837, A189850, A189851, A189852 %K A189853 nonn,hard %O A189853 1,2 %A A189853 _Vaclav Kotesovec_, Apr 29 2011