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Search: id:A033507
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| A033507 |
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Number of matchings in graph P_{4} X P_{n} |
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+0
4
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| 5, 71, 823, 10012, 120465, 1453535, 17525619, 211351945, 2548684656, 30734932553, 370635224561, 4469527322891, 53898461609719, 649966808093412, 7838012982224913, 94519361817920403
(list; graph; listen)
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OFFSET
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0,1
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REFERENCES
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Per Hakan Lundow, "Computation of matching polynomials and the number of 1-factors in polygraphs", Research reports, No 12, 1996, Department of Mathematics, Umea University.
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LINKS
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Per Hakan Lundow, Enumeration of matchings in polygraphs, 1998.
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EXAMPLE
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a(0) = 5: the graph is
. o-o-o-o
and the five matchings are
. o o o o
. o-o o o
. o o-o o
. o o o-o
. o-o o-o
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CROSSREFS
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For perfect matchings see A005178.
Cf. A033508-A033511.
Sequence in context: A139930 A123077 A064752 this_sequence A092250 A133990 A120808
Adjacent sequences: A033504 A033505 A033506 this_sequence A033508 A033509 A033510
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KEYWORD
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nonn,new
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AUTHOR
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Per Hakan Lundow (phl(AT)theophys.kth.se)
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EXTENSIONS
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Edited by njas, Nov 15 2009
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