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A003776
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Number of 2-factors in P_5 X P_2n.
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0
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3, 54, 1140, 24360, 521064, 11146656, 238452456, 5101047216, 109123156248, 2334395822496, 49938107061384, 1068291209653392, 22853211220567416, 488882861126970624
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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REFERENCES
| F. Faase, On the number of specific spanning subgraphs of the graphs G X P_n, Ars Combin. 49 (1998), 129-154.
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LINKS
| 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 Hamilton cycles in product graphs
F. Faase, Results from the counting program
F. Faase, Counting Hamilton cycles in product graphs
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FORMULA
| a(n) = 24a(n-1) - 57a(n-2) + 26a(n-3), n>3.
a(n)=(2/3)*sqrt(3)*[11+6*sqrt(3)]^n-(2/3)*sqrt(3)*[11-6*sqrt(3)]^n+(1/3)*2^n+(4/3)*[11-6 *sqrt(3)]^n+(4/3)*[11+6*sqrt(3)]^n, with n>=0 - Paolo P. Lava (paoloplava(AT)gmail.com), Jun 17 2008
G.f.: 3x(1-5x)(1-x)/((1-2x)(1-22x+13x^2)). [From R. J. Mathar (mathar(AT)strw.leidenuniv.nl), Dec 16 2008]
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CROSSREFS
| Sequence in context: A119294 A157541 A065102 * A157550 A091826 A091796
Adjacent sequences: A003773 A003774 A003775 * A003777 A003778 A003779
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KEYWORD
| nonn
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AUTHOR
| Frans Faase (Frans_LiXia(AT)wxs.nl)
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