A143877 Number of ways of placing kings with no more than 2 mutual attacks on an n X n chessboard symmetric under horizontal and vertical reflection.
1, 2, 1, 7, 4, 55, 17, 576, 129, 13243, 1554, 465675, 35443, 32233206, 1330673, 3746034675, 92945020
Offset: 0