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Search: id:A000949
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| A000949 |
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Number of forests with n nodes and height at most 2.
(Formerly M3021 N1223)
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+0
12
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| 1, 3, 16, 101, 756, 6607, 65794, 733833, 9046648, 121961051, 1782690174, 28055070397, 472594822324, 8479144213191, 161340195463066, 3243707386310033, 68679247688467056, 1526976223741111987
(list; graph; listen)
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OFFSET
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1,2
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REFERENCES
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N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
N. J. A. Sloane, A Handbook of Integer Sequences, Academic Press, 1973 (includes this sequence).
J. Riordan, Forests of labeled trees, J. Combin. Theory, 5 (1968), 90-103.
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FORMULA
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E.g.f.: exp(x*exp(x*exp(x))).
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CROSSREFS
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Cf. A000248, A000950, A000951, A052512-A052514.
Sequence in context: A137572 A009151 A009007 this_sequence A091637 A074542 A105622
Adjacent sequences: A000946 A000947 A000948 this_sequence A000950 A000951 A000952
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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 from Vladeta Jovovic (vladeta(AT)eunet.rs), Apr 07 2001
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