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Search: id:A045310
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| A045310 |
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Number of matchings in n-cube. |
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+0
3
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| 2, 7, 108, 41025, 13803794944, 7174574164703330195841
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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a(4)=A033532(0), a(5)=A033532(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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Comment from Max Alekseyev, Nov 16 2009: E.g. for n=2, we have
1 matching of size 0 (i.e. the empty matching)
4 matchings of size 1 (i.e. an edge)
2 matchings of size 2 (that are the perfect matchings).
So a(2) = 1 + 4 + 2 = 7, whereas A005271(2) = 2.
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CROSSREFS
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For perfect matchings see A005271.
Cf. A033532.
Sequence in context: A122524 A162634 A072664 this_sequence A000157 A034902 A101429
Adjacent sequences: A045307 A045308 A045309 this_sequence A045311 A045312 A045313
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KEYWORD
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nonn,hard,more
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AUTHOR
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Per Hakan Lundow (phl(AT)theophys.kth.se)
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