Number of ways to place 2 nonattacking queens on an n X n toroidal board.

Terms

a(0) =0a(1) =0a(2) =0a(3) =32a(4) =100a(5) =288a(6) =588a(7) =1152a(8) =1944a(9) =3200a(10) =4840a(11) =7200a(12) =10140a(13) =14112a(14) =18900a(15) =25088a(16) =32368a(17) =41472a(18) =51984a(19) =64800a(20) =79380a(21) =96800a(22) =116380a(23) =139392a(24) =165000a(25) =194688a(26) =227448a(27) =264992a(28) =306124a(29) =352800