A220823 Number of rooted gene trees with n leaves on the label set [3].

3, 6, 28, 156, 948, 6206, 42504, 301548, 2195100, 16307598, 123128940, 942125110, 7289062320, 56926578912, 448186662992, 3553364598786, 28345260090444, 227337020914322, 1832102040838776, 14828608892376288, 120485979704314764, 982422914174633154, 8036158136627878572

Offset

1,1

Links

Andrew Howroyd, Table of n, a(n) for n = 1..200

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

Crossrefs

Column 3 of A319254.

Sequence in context: A068808 A068133 A370668 * A024497 A007228 A326074

Adjacent sequences: A220820 A220821 A220822 * A220824 A220825 A220826

Keyword

nonn

Author

N. J. A. Sloane, Dec 22 2012

Extensions

Terms a(11) and beyond from Andrew Howroyd, Sep 17 2018

Status

approved