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 A189852 #6 Sep 12 2015 11:00:25 %S A189852 1,2,6,24,120,336,1474,8340,57756,475658,2812910,20852460,181255892, %T A189852 1817101242,20435345782,197871434994 %N A189852 Number of ways to place n nonattacking composite pieces rook + rider[1,5] on an n X n chessboard. %C A189852 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 for all i>=1, j>=1, k>=1, i+k<=n, j+5k<=n %H A189852 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 A189852 Wikipedia, <a href="http://en.wikipedia.org/wiki/Fairy_chess_piece">Fairy chess piece</a> %Y A189852 Cf. A000170, A189837, A189850, A189851 %K A189852 nonn,hard %O A189852 1,2 %A A189852 _Vaclav Kotesovec_, Apr 29 2011