A130712 Number of ways of placing non-attacking knights on an n X n chessboard symmetric about the diagonal and under 90-degree rotation.

1, 2, 2, 6, 3, 21, 12, 118, 56, 959, 333, 9892, 3038, 154506, 38869, 3291314, 689349, 103050492, 17202265, 4328976863, 615532072, 271539093065, 30694296121, 22908330863086, 2181826599454, 2875160955130336, 217661432837240

Offset

0,2

Links

Table of n, a(n) for n=0..26.

Crossrefs

Sequence in context: A305814 A266479 A296147 * A276075 A321908 A130728

Adjacent sequences: A130709 A130710 A130711 * A130713 A130714 A130715

Keyword

nonn

Author

R. H. Hardin, Aug 25 2008

Status

approved