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Number of ways to place n nonattacking composite pieces queen + rider[2,5] on an n X n chessboard.
2

%I #6 Sep 12 2015 11:00:25

%S 1,0,0,2,10,4,28,20,56,72,200,644,2940,9152,39200,166100,739924,

%T 3586840,18640500,107580592,547737844,3080550788

%N Number of ways to place n nonattacking composite pieces queen + rider[2,5] on an n X n chessboard.

%C a(n) is also number of permutations p of 1,2,...,n satisfying |p(i+2k)-p(i)|<>5k AND |p(j+5k)-p(j)|<>2k AND |p(m+k)-p(m)|<>k for all i>=1, j>=1, m>=1, k>=1, i+2k<=n, j+5k<=n, m+k<=n

%H 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 Wikipedia, <a href="http://en.wikipedia.org/wiki/Fairy_chess_piece">Fairy chess piece</a>

%Y Cf. A102388, A189875, A189876, A189877, A189856

%K nonn,hard

%O 1,4

%A _Vaclav Kotesovec_, Apr 29 2011