Number of ways to place 4 nonattacking amazons (superqueens) on an n X n toroidal board.

Terms

a(0) =0a(1) =0a(2) =0a(3) =0a(4) =0a(5) =0a(6) =98a(7) =3328a(8) =17496a(9) =99600a(10) =316052a(11) =1041408a(12) =2501538a(13) =6157536a(14) =12531150a(15) =25938944a(16) =47168268a(17) =86938272a(18) =145818008a(19) =247240000a(20) =390084786a(21) =620964256a(22) =933865918a(23) =1414946304a(24) =2047225000a(25) =2980849040a(26) =4177648224a(27) =5886858432a(28) =8032809818a(29) =11012886000