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A189867
Number of ways to place n nonattacking composite pieces queen + leaper[2,3] on an n X n chessboard.
2
1, 0, 0, 2, 10, 0, 0, 0, 0, 48, 152, 472, 2696, 12320, 74436, 429620, 2515116, 16122496, 113016608, 843492920, 6575649316, 54694203188
OFFSET
1,4
COMMENTS
In fairy chess the leaper [2,3] is called a zebra.
a(n) is also number of permutations p of 1,2,...,n satisfying |p(i+2)-p(i)|<>3 AND |p(j+3)-p(j)|<>2 AND |p(m+k)-p(m)|<>k for all i>=1, j>=1, m>=1, k>=1, i+2<=n, j+3<=n, m+k<=n
CROSSREFS
KEYWORD
nonn,hard
AUTHOR
Vaclav Kotesovec, Apr 29 2011
STATUS
approved