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Number of ways to place n nonattacking composite pieces queen + rider[1,4] on an n X n chessboard.
3

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

%S 1,0,0,2,10,0,0,4,8,28,100,186,624,1720,7288,30666,100220,360208,

%T 1517804,7302336,29429672,139854636,753288744

%N Number of ways to place n nonattacking composite pieces queen + rider[1,4] on an n X n chessboard.

%C (in fairy chess the rider [1,4] is called a Girafferider)

%C a(n) is also number of permutations p of 1,2,...,n satisfying |p(i+k)-p(i)|<>4k AND |p(j+4k)-p(j)|<>k AND |p(m+k)-p(m)|<>k for all i>=1, j>=1, m>=1, k>=1, i+k<=n, j+4k<=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, A189873, A189851

%K nonn,hard

%O 1,4

%A _Vaclav Kotesovec_, Apr 29 2011