Number of ways to place 4 nonattacking bishops on an n X n toroidal board.

Terms

a(0) =0a(1) =0a(2) =0a(3) =64a(4) =600a(5) =6912a(6) =29400a(7) =132864a(8) =381024a(9) =1139200a(10) =2613600a(11) =6177600a(12) =12269400a(13) =24912384a(14) =44717400a(15) =81636352a(16) =135945600a(17) =229423104a(18) =360561024a(19) =572788800a(20) =859685400a(21) =1301766400a(22) =1881864600a(23) =2740725504a(24) =3840540000