A003758 Number of 2-factors in D_4 X P_n.

0, 3, 7, 46, 193, 963, 4470, 21367, 100909, 478924, 2268405, 10753173, 50957032, 241508575, 1144553203, 5424374574, 25707458901, 121834519567, 577405414054, 2736475971043, 12968875078785, 61462896633780

Offset

1,2

References

F. Faase, On the number of specific spanning subgraphs of the graphs G X P_n, Ars Combin. 49 (1998), 129-154.

Links

Table of n, a(n) for n=1..22.

F. Faase, On the number of specific spanning subgraphs of the graphs G X P_n, Preliminary version of paper that appeared in Ars Combin. 49 (1998), 129-154.

F. Faase, Counting Hamiltonian cycles in product graphs

F. Faase, Results from the counting program

Index entries for linear recurrences with constant coefficients, signature (3, 9, -3, -3, 1).

Formula

a(n) = 3a(n-1) + 9a(n-2) - 3a(n-3) - 3a(n-4) + a(n-5), n>5.

G.f.: x^2*(1-x)(-x^2+x+3)/(1-3x-9x^2+3x^3+3x^4-x^5). [From R. J. Mathar, Dec 16 2008]

Crossrefs

Sequence in context: A301324 A184339 A294915 * A231893 A132565 A129518

Adjacent sequences: A003755 A003756 A003757 * A003759 A003760 A003761

Keyword

nonn

Author

Frans J. Faase

Status

approved