Number of non-attacking placements of 4 rooks on an n X n board.

Terms

a(0) =0a(1) =0a(2) =0a(3) =24a(4) =600a(5) =5400a(6) =29400a(7) =117600a(8) =381024a(9) =1058400a(10) =2613600a(11) =5880600a(12) =12269400a(13) =24048024a(14) =44717400a(15) =79497600a(16) =135945600a(17) =224726400a(18) =360561024a(19) =563376600a(20) =859685400a(21) =1284221400a(22) =1881864600a(23) =2709885024a(24) =3840540000a(25) =5364060000