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A005588
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Number of free binary rooted trees of height n.
(Formerly M1813)
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3
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2, 7, 52, 2133, 2590407, 3374951541062, 5695183504479116640376509, 16217557574922386301420514191523784895639577710480, 131504586847961235687181874578063117114329409897550318273792033024340388219235081096658023517076950
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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REFERENCES
| F. Harary et al., Counting free binary trees..., J. Combin. Inform. System Sciences, 17 (1992), 175-181.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
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LINKS
| David Wasserman, Table of n, a(n) for n = 1..12
David Wasserman, Table of n, a(n) for n = 1..21
Index entries for sequences related to rooted trees
Index entries for sequences related to trees
Index entries for "core" sequences
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FORMULA
| Reference gives a complicated recurrence.
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CROSSREFS
| Cf. A002658, A006894.
Sequence in context: A138737 A046662 A118191 * A106898 A106899 A119772
Adjacent sequences: A005585 A005586 A005587 * A005589 A005590 A005591
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KEYWORD
| nonn,easy,core,nice
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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