A143883 Number of ways of placing kings with no more than 3 mutual attacks on an n X n chessboard symmetric about main diagonal.

1, 2, 7, 29, 160, 1135, 10529, 125770, 1963039, 39868375, 1061669314, 37110747097, 1708827058427

Offset

0,2

Links

Table of n, a(n) for n=0..12.

Crossrefs

Sequence in context: A030956 A329259 A185310 * A346427 A003437 A192410

Adjacent sequences: A143880 A143881 A143882 * A143884 A143885 A143886

Keyword

nonn,more,hard

Author

R. H. Hardin, Sep 04 2008

Status

approved