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