A220831 Number of unrooted binary leaf-multi-labeled trees with n leaves on the label set [4], with each label used at least once.

0, 0, 0, 3, 36, 310, 2376, 17304, 123508, 874998, 6197220, 44035861, 314538360, 2260572810, 16353884828, 119102737971, 873124996284, 6441569967712, 47813037934740, 356947999429560, 2679333805629928, 20214890317096644, 153250432833122904, 1167042280999763748

Offset

1,4

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 4 of A339650.

Sequence in context: A212616 A073980 A034860 * A003691 A038146 A067444

Adjacent sequences: A220828 A220829 A220830 * A220832 A220833 A220834

Keyword

nonn

Author

N. J. A. Sloane, Dec 22 2012

Extensions

Terms a(11) and beyond from Andrew Howroyd, Dec 14 2020

Status

approved