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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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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; refs; listen; history; internal format)
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OFFSET
| 0,4
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REFERENCES
| G. W. Ford and G. E. Uhlenbeck, Combinatorial problems in the theory of graphs III, Proc. Nat. Acad. Sci. USA, 42 (1956), 529-535.
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
| 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
| 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
| Cf. A000237, A000314, A035082, A035349-A035357.
Sequence in context: A058585 A001573 A135307 * A092668 A164039 A014137
Adjacent sequences: A000080 A000081 A000082 * A000084 A000085 A000086
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KEYWORD
| nonn
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
| More terms and formula from Christian G. Bower (bowerc(AT)usa.net), Nov 15 1998
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