Number of ways to place a non-attacking white and black rook on n X n chessboard.

Terms

a(0) =0a(1) =4a(2) =36a(3) =144a(4) =400a(5) =900a(6) =1764a(7) =3136a(8) =5184a(9) =8100a(10) =12100a(11) =17424a(12) =24336a(13) =33124a(14) =44100a(15) =57600a(16) =73984a(17) =93636a(18) =116964a(19) =144400a(20) =176400a(21) =213444a(22) =256036a(23) =304704a(24) =360000a(25) =422500a(26) =492804a(27) =571536a(28) =659344a(29) =756900