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

Author

N. J. A. Sloane, Dec 22 2012

Keywords

• nonn

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.

Extensions

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