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Search: id:A038049
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| A038049 |
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Number of labeled rooted trees with 2-colored leaves. |
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+0
8
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| 2, 4, 24, 224, 2880, 47232, 942592, 22171648, 600698880, 18422374400, 630897721344, 23864653578240, 988197253808128, 44460603225407488, 2159714024218951680, 112652924603290615808, 6280048587936003784704
(list; graph; listen)
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OFFSET
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1,1
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REFERENCES
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F. Bergeron, G. Labelle and P. Leroux, Combinatorial Species and Tree-Like Structures, Cambridge, 1998, p. 185 (3.1.83)
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LINKS
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N. J. A. Sloane, Transforms
Index entries for sequences related to rooted trees
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FORMULA
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Divides by n and shifts left under exponential transform.
E.g.f.: x-LambertW(-x*exp(x)). - Vladeta Jovovic (vladeta(AT)eunet.rs), Mar 08 2003
a(n) = Sum_{k=0..n} (binomial(n, k)*(n-k)^(n-1)).
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CROSSREFS
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Cf. A000169, A029856, A038050, A038054.
Sequence in context: A121892 A032107 A141307 this_sequence A151817 A038058 A062531
Adjacent sequences: A038046 A038047 A038048 this_sequence A038050 A038051 A038052
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KEYWORD
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nonn,eigen
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AUTHOR
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Christian G. Bower (bowerc(AT)usa.net), Jan 04 1999.
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