Number of chordless cycles in the n X n rook complement graph.

Terms

a(0) =0a(1) =0a(2) =15a(3) =264a(4) =1700a(5) =6900a(6) =21315a(7) =54880a(8) =123984a(9) =253800a(10) =480975a(11) =856680a(12) =1450020a(13) =2351804a(14) =3678675a(15) =5577600a(16) =8230720a(17) =11860560a(18) =16735599a(19) =23176200a(20) =31560900a(21) =42333060a(22) =56007875a(23) =73179744a(24) =94530000a(25) =120835000a(26) =152974575a(27) =191940840a(28) =238847364a(29) =294938700