Number of ways to place 4 nonattacking kings on an n X n toroidal board.

Terms

a(0) =0a(1) =0a(2) =0a(3) =12a(4) =575a(5) =9837a(6) =63553a(7) =265008a(8) =853497a(9) =2312925a(10) =5532967a(11) =12037068a(12) =24293243a(13) =46125317a(14) =83243925a(15) =143918272a(16) =239811333a(17) =387002853a(18) =607226187a(19) =929346700a(20) =1391111127a(21) =2041198973a(22) =2941608713a(23) =4170413232a(24) =5824920625a(25) =8025278157a(26) =10918558863a(27) =14683371948a(28) =19535039827a(29) =25731386325