Number of ways 4 domicules can be placed on an n X n square.

Terms

a(0) =0a(1) =0a(2) =0a(3) =58a(4) =18343a(5) =362643a(6) =2911226a(7) =14601844a(8) =54738489a(9) =168157793a(10) =446728228a(11) =1062085146a(12) =2312934779a(13) =4690690399a(14) =8967633918a(15) =16312226288a(16) =28436620141a(17) =47781858189a(18) =77746670984a(19) =122966217718a(20) =189647543823a(21) =285968959211a(22) =422550971074a(23) =613006835244