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

Terms

a(0) =0a(1) =2a(2) =18a(3) =72a(4) =200a(5) =378a(6) =588a(7) =1312a(8) =2106a(9) =3650a(10) =4840a(11) =7848a(12) =10140a(13) =14210a(14) =20250a(15) =25728a(16) =32368a(17) =42282a(18) =51984a(19) =67400a(20) =80262a(21) =97042a(22) =116380a(23) =141984a(24) =167500a(25) =195026a(26) =228906a(27) =266952a(28) =306124a(29) =358650