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A220830 Number of unrooted binary leaf-multi-labeled trees with n leaves on the label set [3], with each label used at least once. 0
0, 0, 1, 6, 30, 140, 663, 3186, 15642, 78441 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

LINKS

Table of n, a(n) for n=1..10.

V. P. Johnson, Enumeration Results on Leaf Labeled Trees, Ph. D. Dissertation, Univ. Southern Calif., 2012.

CROSSREFS

Sequence in context: A082149 A002457 A137400 * A199938 A285195 A307321

Adjacent sequences:  A220827 A220828 A220829 * A220831 A220832 A220833

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Dec 22 2012

STATUS

approved

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Last modified June 19 23:56 EDT 2019. Contains 324222 sequences. (Running on oeis4.)