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A143879
Number of ways of placing kings with no more than 2 mutual attacks on an n X n chessboard symmetric about both diagonal and antidiagonal.
1
1, 2, 3, 7, 12, 41, 85, 434, 1009, 7325, 21498, 219307, 803859, 11370922
OFFSET
0,2
CROSSREFS
Sequence in context: A056356 A084708 A035003 * A056293 A275311 A056294
KEYWORD
nonn,more,hard
AUTHOR
R. H. Hardin, Sep 04 2008
STATUS
approved