Number of cliques in the n X n rook graph.

Terms

a(0) =1a(1) =2a(2) =9a(3) =34a(4) =105a(5) =286a(6) =721a(7) =1730a(8) =4017a(9) =9118a(10) =20361a(11) =44914a(12) =98137a(13) =212798a(14) =458529a(15) =982786a(16) =2096865a(17) =4456126a(18) =9436825a(19) =19922546a(20) =41942601a(21) =88079902a(22) =184548849a(23) =385875394a(24) =805305745a(25) =1677720926a(26) =3489660201a(27) =7247756530a(28) =15032384697a(29) =31138511998