|
Search: id:A071213
|
|
|
| A071213 |
|
Number of labeled planar trees with n nodes such that the root is smaller than all its children. |
|
+0
1
|
|
| 1, 4, 34, 436, 7428, 157368, 3980688, 116949600, 3911421600, 146673662400, 6093249563520, 277729608280320, 13778539159795200, 739059210587980800, 42615627311477606400, 2628646012982829772800, 172704619437756321484800
(list; graph; listen)
|
|
|
OFFSET
|
2,2
|
|
|
REFERENCES
|
C. Chauve, S. Dulucq and O. Guibert, Enumeration of some labeled trees, research report RR-1226-99, LaBRI, Bordeaux I University, 1999.
|
|
MAPLE
|
n -> 2 * sum((n-1) * (n-2+k)! / (k! * (n-1-k)), k=0 .. n-2) - ((2*n-3)! / (n-2)!);
|
|
CROSSREFS
|
Cf. A000312.
Sequence in context: A158839 A145349 A052630 this_sequence A052629 A151919 A156325
Adjacent sequences: A071210 A071211 A071212 this_sequence A071214 A071215 A071216
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Cedric Chauve (chauve(AT)lacim.uqam.ca), May 16 2002
|
|
|
Search completed in 0.002 seconds
|
