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A145409
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Number of perfect matchings (or domino tilings) in K_6 X P_n.
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0
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15, 376, 8805, 207901, 4903920, 115686901, 2729093235, 64380355576, 1518756918825, 35828050696201, 845197277027040, 19938523685081401, 470357320740846855, 11095907233164566776, 261756651587724670845
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OFFSET
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1,1
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REFERENCES
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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
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FORMULA
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Recurrence:
a(1) = 15,
a(2) = 376,
a(3) = 8805,
a(4) = 207901, and
a(n) = 21a(n-1) + 62a(n-2) - 21a(n-3) - a(n-4).
G.f.: x(15+61x-21x^2-x^3)/(1-21x-62x^2+21x^3+x^4). - R. J. Mathar, Feb 19 2009
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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