Number of 2-factors in D_4 X P_n.

Terms

a(0) =0a(1) =3a(2) =7a(3) =46a(4) =193a(5) =963a(6) =4470a(7) =21367a(8) =100909a(9) =478924a(10) =2268405a(11) =10753173a(12) =50957032a(13) =241508575a(14) =1144553203a(15) =5424374574a(16) =25707458901a(17) =121834519567a(18) =577405414054