

A189859


Number of ways to place n nonattacking composite pieces rook + rider[3,5] on an n X n chessboard.


2



1, 2, 6, 24, 120, 464, 2274, 13236, 91760, 740562, 5305548, 43237840, 395858894, 4087066620, 46633569480, 509698057110
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OFFSET

1,2


COMMENTS

a(n) is also number of permutations p of 1,2,...,n satisfying p(i+3k)p(i)<>5k AND p(j+5k)p(j)<>3k for all i>=1, j>=1, k>=1, i+3k<=n, j+5k<=n


LINKS



CROSSREFS



KEYWORD

nonn,hard


AUTHOR



STATUS

approved



