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A143893
Number of ways of placing kings with no more than 4 mutual attacks on an n X n chessboard symmetric under 180 degree rotation.
2
1, 2, 3, 19, 62, 785, 3961, 92618, 796423, 31554358, 442143014
OFFSET
0,2
CROSSREFS
Sequence in context: A157042 A128968 A153409 * A262957 A072263 A009178
KEYWORD
nonn,more,hard
AUTHOR
R. H. Hardin, Sep 04 2008
STATUS
approved