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A145410 Number of 2-factors in K_6 X P_n. 0
70, 24400, 6912340, 1997380720, 576043535680, 166162145824000, 47929270990315840, 13825165615038910720, 3987858909906969326080, 1150295005804962553753600, 331801758293292909512074240, 95707976014178819083415941120, 27606896116821809366222931066880 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

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..13.

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 (264,7160,-31008,-10480).

FORMULA

Recurrence:

a(1) = 70,

a(2) = 24400,

a(3) = 6912340,

a(4) = 1997380720, and

a(n) = 264a(n-1) + 7160a(n-2) - 31008a(n-3) - 10480a(n-4).

G.f.: -10*x*(1048*x^3+3046*x^2-592*x-7)/(10480*x^4+31008*x^3-7160*x^2-264*x+1). [Colin Barker, Aug 30 2012]

MAPLE

a:= n-> (<<264|7160|-31008|-10480>, <1|0|0|0>, <0|1|0|0>, <0|0|1|0>>^n. <<6912340, 24400, 70, 1>>)[4, 1]: seq(a(n), n=1..15); # Alois P. Heinz, Sep 20 2011

MATHEMATICA

a[1] = 70; a[2] = 24400; a[3] = 6912340; a[4] = 1997380720; a[n_] := a[n] = 264*a[n-1] + 7160*a[n-2] - 31008*a[n-3] - 10480*a[n-4]; Array[a, 13] (* Jean-Fran├žois Alcover, Mar 18 2014 *)

CROSSREFS

Sequence in context: A004109 A002829 A177637 * A177638 A274646 A005983

Adjacent sequences:  A145407 A145408 A145409 * A145411 A145412 A145413

KEYWORD

nonn,easy

AUTHOR

N. J. A. Sloane, Feb 03 2009

STATUS

approved

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Last modified November 26 03:20 EST 2020. Contains 338632 sequences. (Running on oeis4.)