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

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =24a(5) =204a(6) =1024a(7) =3628a(8) =10320a(9) =25096a(10) =54400a(11) =107880a(12) =199400a(13) =348020a(14) =579264a(15) =926324a(16) =1431584a(17) =2148048a(18) =3141120a(19) =4490256a(20) =6291000a(21) =8656860a(22) =11721600a(23) =15641340a(24) =20597104a(25) =26797144a(26) =34479744a(27) =43915768a(28) =55411720a(29) =69312516