|
| |
|
|
A078792
|
|
Number of unlabeled 3-trees on n vertices.
|
|
4
|
|
|
|
0, 0, 1, 1, 1, 2, 5, 15, 58, 275, 1505, 9003, 56931, 372973, 2506312, 17165954, 119398333, 841244274, 5993093551, 43109340222, 312747109787, 2286190318744, 16826338257708, 124605344758149, 927910207739261, 6945172081954449, 52225283886702922
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,6
|
|
|
COMMENTS
|
A k-tree is recursively defined as follows: K_k is a k-tree and any k-tree on n+1 vertices is obtained by joining a new vertex to a k-clique in a k-tree 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..27.
Andrew Gainer-Dewar, Gamma-Species and the Enumeration of k-Trees, Electronic Journal of Combinatorics, Volume 19 (2012), #P45. - From N. J. A. Sloane, Dec 15 2012
|
|
|
CROSSREFS
|
Cf. A036362 (labeled 3-trees), A054581 (unlabeled 2-trees).
Sequence in context: A334155 A348365 A048192 * A208808 A266682 A325575
Adjacent sequences: A078789 A078790 A078791 * A078793 A078794 A078795
|
|
|
KEYWORD
|
nonn
|
|
|
AUTHOR
|
Gordon F. Royle, Dec 05 2002
|
|
|
EXTENSIONS
|
More terms from Andrew R. Gainer, Dec 03 2011
|
|
|
STATUS
|
approved
|
| |
|
|
