|
Search: id:A005354
|
|
|
| A005354 |
|
Number of asymmetric planar trees with n nodes.
(Formerly M2808)
|
|
+0
3
|
|
| 1, 1, 0, 0, 0, 1, 3, 9, 28, 85, 262, 827, 2651, 8626, 28507, 95393, 322938, 1104525, 3812367, 13266366, 46504495, 164098390, 582521687, 2079133141, 7457788295, 26872946466, 97238824018, 353218128299, 1287657977946, 4709784136316
(list; graph; listen)
|
|
|
OFFSET
|
0,7
|
|
|
REFERENCES
|
N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
G. Labelle, Counting asymmetric enriched trees. J. Symbolic Comput. 14 (1992), no. 2-3, 211-242.
|
|
LINKS
|
Index entries for sequences related to trees
|
|
FORMULA
|
G.f.: 1+B(x)+(C(x^2)-C(x)^2)/2 where B is g.f. of A022553(n-1) and C is g.f. of A000108(n-1).
a(n)=A022553(n-1) - A000108(n-2)/2 - (if n is even) A000108(n/2-1)/2.
|
|
CROSSREFS
|
Cf. A000108, A002995, A022553.
Sequence in context: A027099 A027090 A033139 this_sequence A084084 A091140 A052541
Adjacent sequences: A005351 A005352 A005353 this_sequence A005355 A005356 A005357
|
|
KEYWORD
|
nonn,nice
|
|
AUTHOR
|
N. J. A. Sloane (njas(AT)research.att.com), Simon Plouffe, Susanna Cuyler
|
|
EXTENSIONS
|
More terms, formula from Christian G. Bower (bowerc(AT)usa.net), Dec 15 1999.
|
|
|
Search completed in 0.002 seconds
|
