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A145409
Number of perfect matchings (or domino tilings) in K_6 X P_n.
0
15, 376, 8805, 207901, 4903920, 115686901, 2729093235, 64380355576, 1518756918825, 35828050696201, 845197277027040, 19938523685081401, 470357320740846855, 11095907233164566776, 261756651587724670845
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
FORMULA
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
CROSSREFS
Sequence in context: A087330 A035274 A324415 * A164323 A374000 A129615
KEYWORD
nonn
AUTHOR
N. J. A. Sloane, Feb 03 2009
EXTENSIONS
More terms from R. J. Mathar, Feb 19 2009
STATUS
approved