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

Terms

a(0) =0a(1) =0a(2) =0a(3) =16a(4) =78a(5) =228a(6) =520a(7) =1020a(8) =1806a(9) =2968a(10) =4608a(11) =6840a(12) =9790a(13) =13596a(14) =18408a(15) =24388a(16) =31710a(17) =40560a(18) =51136a(19) =63648a(20) =78318a(21) =95380a(22) =115080a(23) =137676a(24) =163438a(25) =192648a(26) =225600a(27) =262600a(28) =303966a(29) =350028