A359398 - OEIS

A359398

Number of unlabeled trees covering 2n nodes, half of which are leaves.

0, 1, 2, 8, 32, 158, 833, 4755, 28389, 176542, 1131055, 7432876, 49873477, 340658595, 2362652648, 16605707901, 118082160358, 848399575321, 6152038125538, 44981009272740, 331344933928536, 2457372361637286, 18337490246234464, 137612955519565773, 1038076541372187991

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,3

LINKS

Andrew Howroyd, Table of n, a(n) for n = 1..100

Gus Wiseman, The a(4) = 8 trees covering 8 nodes, half of which are leaves.

FORMULA

a(n) = A055290(2*n, n). - Andrew Howroyd, Jan 01 2023

CROSSREFS

Left of central column of A055290.

The labeled version is the left of central column of A055314.

The rooted version is A185650.

For n+1 leaves we have A358107.

The labeled version is A358732.

A000272 counts trees, bisection A163395, unlabeled A000055.

A001187 counts connected graphs, unlabeled A001349.

A006125 counts graphs, unlabeled A000088.

A006129 counts covering graphs, unlabeled A002494.

A014068 counts graphs with n vertices and n-1 edges, unlabeled A001433.

Sequence in context: A348905 A131785 A347363 * A006669 A193778 A030804

Adjacent sequences: A359395 A359396 A359397 * A359399 A359400 A359401

KEYWORD

nonn

AUTHOR

Gus Wiseman, Jan 01 2023

EXTENSIONS

Terms a(12) and beyond from Andrew Howroyd, Jan 01 2023

STATUS

approved