

A145405


Number of 2factors in O_6 X P_n.


1



20, 2984, 340852, 40071100, 4696965476, 550730736140, 64572426811780, 7571054816109868, 887698562638519076, 104081767587749759756, 12203482981057263416260, 1430846154730977823707628, 167765278289617542860512868, 19670310820391775621430114508
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OFFSET

1,1


REFERENCES

F. Faase, On the number of specific spanning subgraphs of the graphs G X P_n, Ars Combin. 49 (1998), 129154.


LINKS

Alois P. Heinz, Table of n, a(n) for n = 1..150
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), 129154.
F. Faase, Counting Hamiltonian cycles in product graphs.
F. Faase, Results from the counting program
Index entries for linear recurrences with constant coefficients, signature (113,585,10329,17644,3148,8496).


FORMULA

Recurrence:
a(1) = 20,
a(2) = 2984,
a(3) = 340852,
a(4) = 40071100,
a(5) = 4696965476,
a(6) = 550730736140, and
a(n) = 113a(n1) + 585a(n2)  10329a(n3) + 17644a(n4) + 3148a(n5)  8496a(n6).
G.f.: 4*x*(2124*x^5403*x^43941*x^3+2010*x^2181*x5) / (8496*x^6 3148*x^5 17644*x^4 +10329*x^3 585*x^2 113*x+1). [Colin Barker, Aug 23 2012]


MAPLE

a:= n> (Matrix (6, (i, j)> `if` (i=j1, 1, `if` (i=6, [8496, 3148, 17644, 10329, 585, 113][j], 0)))^n. <<1, 20, 2984, 340852, 40071100, 4696965476>>) [1, 1]: seq (a(n), n=1..20); # Alois P. Heinz, Aug 28, 2011


CROSSREFS

Sequence in context: A222943 A222750 A250019 * A028458 A225989 A332265
Adjacent sequences: A145402 A145403 A145404 * A145406 A145407 A145408


KEYWORD

nonn,easy


AUTHOR

N. J. A. Sloane, Feb 03 2009


STATUS

approved



