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 A003776 Number of 2-factors in P_5 X P_2n. 1
 3, 54, 1140, 24360, 521064, 11146656, 238452456, 5101047216, 109123156248, 2334395822496, 49938107061384, 1068291209653392, 22853211220567416, 488882861126970624 (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 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, Results from the counting program 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, Jun 17 2008 G.f.: 3x(1-5x)(1-x)/((1-2x)(1-22x+13x^2)). [From R. J. Mathar, Dec 16 2008] CROSSREFS Sequence in context: A182159 A065102 A223926 * A222203 A224051 A355365 Adjacent sequences: A003773 A003774 A003775 * A003777 A003778 A003779 KEYWORD nonn AUTHOR STATUS approved

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Last modified January 31 08:00 EST 2023. Contains 359950 sequences. (Running on oeis4.)