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Search: id:A000083
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| A000083 |
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Number of mixed Husimi trees with n nodes; or polygonal cacti with bridges.
(Formerly M1191 N0461)
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+0
12
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| 1, 1, 1, 2, 4, 9, 23, 63, 188, 596, 1979, 6804, 24118, 87379, 322652, 1209808, 4596158, 17657037, 68497898, 268006183, 1056597059, 4193905901, 16748682185, 67258011248, 271452424286, 1100632738565, 4481533246014
(list; graph; listen)
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OFFSET
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0,4
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REFERENCES
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G. W. Ford and G. E. Uhlenbeck, Combinatorial problems in the theory of graphs III, Proc. Nat. Acad. Sci. USA, 42 (1956), 529-535.
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LINKS
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Christian G. Bower, Table of n, a(n) for n=0..500
Index entries for sequences related to cacti
Index entries for sequences related to trees
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FORMULA
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G.f.: A(x)=B(x)+C(x)-B(x)*D(x), B, C, D resp gfs of A000237, A035349, A035350.
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CROSSREFS
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Cf. A000237, A000314, A035082, A035349-A035357.
Adjacent sequences: A000080 A000081 A000082 this_sequence A000084 A000085 A000086
Sequence in context: A058585 A001573 A135307 this_sequence A092668 A014137 A007476
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
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More terms and formula from Christian G. Bower (bowerc(AT)usa.net), Nov 15 1998
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