Number of ways to place 3 nonattacking knights on an n X n board.

Terms

a(0) =0a(1) =4a(2) =36a(3) =276a(4) =1360a(5) =4752a(6) =13340a(7) =32084a(8) =68796a(9) =135040a(10) =247152a(11) =427380a(12) =705144a(13) =1118416a(14) =1715220a(15) =2555252a(16) =3711620a(17) =5272704a(18) =7344136a(19) =10050900a(20) =13539552a(21) =17980560a(22) =23570764a(23) =30535956a(24) =39133580a(25) =49655552a(26) =62431200a(27) =77830324