Number of 6-cycles in the n X n black bishop graph.

Terms

a(0) =0a(1) =0a(2) =0a(3) =15a(4) =220a(5) =1253a(6) =5412a(7) =15642a(8) =44368a(9) =97158a(10) =218816a(11) =410209a(12) =797052a(13) =1350435a(14) =2367668a(15) =3733284a(16) =6068736a(17) =9065724a(18) =13907808a(19) =19916451a(20) =29188092a(21) =40399953a(22) =57056164a(23) =76789790a(24) =105186576a(25) =138276450a(26) =184618720a(27) =237885141a(28) =310761308a(29) =393568879