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A006681 Number of binary phylogenetic trees with n labels.
(Formerly M3527)
0
1, 4, 16, 85, 646, 6664, 86731, 1354630, 24607816, 509000899, 11802833296, 303129872500, 8539567141561, 261785254856584, 8674697402099836, 308953306192527445, 11768768651529113506, 477433786852228938844 (list; graph; refs; listen; history; text; internal format)
OFFSET
2,2
REFERENCES
Foulds, L. R.; Robinson, R. W. Enumeration of binary phylogenetic trees. Combinatorial mathematics, VIII (Geelong, 1980), pp. 187-202, Lecture Notes in Math., 884, Springer, Berlin-New York, 1981. Math. Rev. 83a:05071.
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
LINKS
L. R. Foulds and R. W. Robinson, Enumeration of binary phylogenetic trees, pp. 187-202, Lecture Notes in Math., 884, Springer, Berlin-New York, 1981. (Annotated scanned copy)
FORMULA
a(n) = Sum_{k=2..n} S(n, k) * A001147(k - 2) where S(n, m) are the Stirling numbers of the second kind. - Sean A. Irvine, Jun 16 2017
CROSSREFS
Sequence in context: A121145 A144882 A298012 * A074876 A238722 A184507
KEYWORD
nonn
AUTHOR
EXTENSIONS
More terms and offset corrected by Sean A. Irvine, Jun 16 2017
STATUS
approved

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Last modified July 24 13:23 EDT 2024. Contains 374584 sequences. (Running on oeis4.)