cp's OEIS Frontend

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.

A189850 Number of ways to place n nonattacking composite pieces rook + rider[1,3] on an n X n chessboard.

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%I A189850 #6 Sep 12 2015 11:00:25
%S A189850 1,2,6,8,24,126,316,1344,7782,33930,172430,1106754,6432236,45188572,
%T A189850 372437930,2728674526,23648822368,233010291526,2083328647344
%N A189850 Number of ways to place n nonattacking composite pieces rook + rider[1,3] on an n X n chessboard.
%C A189850 In fairy chess, the rider [1,3] is called a Camelrider.
%C A189850 a(n) is also number of permutations p of 1,2,...,n satisfying |p(i+k)-p(i)|<>3k AND |p(j+3k)-p(j)|<>k for all i>=1, j>=1, k>=1, i+k<=n, j+3k<=n
%H A189850 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 A189850 Wikipedia, <a href="http://en.wikipedia.org/wiki/Fairy_chess_piece">Fairy chess piece</a>
%Y A189850 Cf. A000170, A189837
%K A189850 nonn,hard
%O A189850 1,2
%A A189850 _Vaclav Kotesovec_, Apr 29 2011