A143887 Number of ways of placing kings with no more than 4 mutual attacks on an n X n chessboard symmetric under horizontal reflection.
1, 2, 3, 35, 60, 2459, 2907, 447758, 410457, 237456332, 154828648, 342431110933, 169227858597, 1508376191950535, 537887672115734
Offset: 0