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%I #7 Dec 14 2018 19:49:51
%S 1,2,4,8,16,168,88,592,712
%N a(n) gives the number of configurations of non-attacking rooks on an n X n chessboard such that the number of distinct directions between the rooks is given by A321531(n).
%e For n = 5, the a(5) = 16 configurations of nonattacking rooks with the maximal number of directions between them are given by the following two chessboards under all eight symmetries of the square.
%e +---+---+---+---+---+
%e 5| X | | | | |
%e +---+---+---+---+---+
%e 4| | | X | | |
%e +---+---+---+---+---+
%e 3| | | | X | |
%e +---+---+---+---+---+
%e 2| | | | | X |
%e +---+---+---+---+---+
%e 1| | X | | | |
%e +---+---+---+---+---+
%e A B C D E
%e +---+---+---+---+---+
%e 5| X | | | | |
%e +---+---+---+---+---+
%e 4| | | | X | |
%e +---+---+---+---+---+
%e 3| | | X | | |
%e +---+---+---+---+---+
%e 2| | | | | X |
%e +---+---+---+---+---+
%e 1| | X | | | |
%e +---+---+---+---+---+
%e A B C D E
%Y Cf. A321531.
%K nonn,more
%O 1,2
%A _Peter Kagey_, Nov 12 2018
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