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, 2, 3, 7, 12, 41, 85, 434, 1009, 7325, 21498, 219307, 803859, 11370922

Offset

0,2

Links

Table of n, a(n) for n=0..13.

Crossrefs

Sequence in context: A056356 A084708 A035003 * A056293 A275311 A056294

Adjacent sequences: A143876 A143877 A143878 * A143880 A143881 A143882

Keyword

nonn,more,hard

Author

R. H. Hardin, Sep 04 2008

Status

approved