

A201702


Number of unlabeled 5trees on n nodes


3



0, 0, 0, 0, 1, 1, 1, 2, 5, 15, 64, 342, 2321, 18578, 168287, 1656209, 17288336, 188006362, 2105867058, 24108331027, 280638347609, 3310098377912, 39462525169310, 474697793413215, 5754095507495584, 70216415130786725, 861924378411516159, 10636562125193377459
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OFFSET

1,8


COMMENTS

A ktree is recursively defined as follows: K_k is a ktree and any ktree on n+1 vertices is obtained by joining a vertex to a kclique in a ktree on n vertices.


REFERENCES

Miklos Bona, editor, Handbook of Enumerative Combinatorics, CRC Press, 2015, page 328.


LINKS

Table of n, a(n) for n=1..28.
Andrew GainerDewar, GammaSpecies and the Enumeration of kTrees, Electronic Journal of Combinatorics, Volume 19 (2012), #P45.  From N. J. A. Sloane, Dec 15 2012


CROSSREFS

Cf. A054581 (unlabeled 2trees), A078792 (unlabeled 3trees), A078793 (unlabeled 4trees).
Sequence in context: A143872 A130756 A078793 * A202037 A322754 A224917
Adjacent sequences: A201699 A201700 A201701 * A201703 A201704 A201705


KEYWORD

nonn


AUTHOR

Andrew R. Gainer, Dec 03 2011


STATUS

approved



