Number of Hamiltonian cycles in C_5 X P_n.

Terms

a(0) =1a(1) =5a(2) =30a(3) =160a(4) =850a(5) =4520a(6) =24040a(7) =127860a(8) =680040a(9) =3616880a(10) =19236840a(11) =102313600a(12) =544168000a(13) =2894227280a(14) =15393318880a(15) =81871340160a(16) =435443220000