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 A189848 #6 Sep 12 2015 11:00:25 %S A189848 1,2,6,24,120,720,4920,37488,319644,3033264,31784280,364902480, %T A189848 4509620040,59768680032,847746532152 %N A189848 Number of ways to place n nonattacking composite pieces rook + semi-rider[6,6] on an n X n chessboard. %C A189848 a(n) is also number of permutations p of 1,2,...,n satisfying p(j+6k)-p(j)<>6k for all j>=1, k>=1, j+6k<=n %C A189848 For information about semi-pieces see semi-bishop (A187235) and semi-queen (A099152). %H A189848 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 A189848 Wikipedia, <a href="http://en.wikipedia.org/wiki/Fairy_chess_piece">Fairy chess piece</a> %Y A189848 Cf. A189285, A099152, A189843, A189844, A189846, A189847, A189842, A187235 %K A189848 nonn,hard %O A189848 1,2 %A A189848 _Vaclav Kotesovec_, Apr 29 2011