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Search: id:A000237
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| A000237 |
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Number of mixed Husimi trees with n nodes; or rooted polygonal cacti with bridges.
(Formerly M2754 N1107)
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+0
12
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| 0, 1, 1, 3, 8, 26, 84, 297, 1066, 3976, 15093, 58426, 229189, 910127, 3649165, 14756491, 60103220, 246357081, 1015406251, 4205873378, 17497745509, 73084575666, 306352303774, 1288328048865, 5433980577776, 22982025183983
(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
C. G. Bower, Transforms (2)
N. J. A. Sloane, Transforms
Index entries for sequences related to cacti
Index entries for sequences related to rooted trees
Index entries for sequences related to trees
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FORMULA
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Shifts left under transform T where Ta = EULER(BIK(a)).
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CROSSREFS
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Cf. A000083, A000314, A035082, A035349-A035357.
Sequence in context: A061812 A009452 A131910 this_sequence A081497 A028270 A124383
Adjacent sequences: A000234 A000235 A000236 this_sequence A000238 A000239 A000240
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KEYWORD
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nonn,eigen,nice,easy
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AUTHOR
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njas
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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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