Number of 2-factors in W_4 X P_n.

Terms

a(0) =1a(1) =13a(2) =85a(3) =673a(4) =5021a(5) =38237a(6) =289089a(7) =2191309a(8) =16594837a(9) =125714929a(10) =952245373a(11) =7213225309a(12) =54639088433a(13) =413885098253