Number of 6-cycles in the n X n rook graph.

Terms

a(0) =0a(1) =0a(2) =60a(3) =1248a(4) =8400a(5) =35520a(6) =114660a(7) =309120a(8) =731808a(9) =1569600a(10) =3114540a(11) =5802720a(12) =10261680a(13) =17367168a(14) =28310100a(15) =44674560a(16) =68527680a(17) =102522240a(18) =150012828a(19) =215186400a(20) =303208080a(21) =420383040a(22) =574335300a(23) =774204288a(24) =1030860000a(25) =1357137600a(26) =1768092300a(27) =2281275360a(28) =2917032048a(29) =3698822400