|
Search: id:A054727
|
|
|
| A054727 |
|
Number of forests of rooted trees with n nodes on a circle without crossing edges. |
|
+0
4
|
|
| 1, 2, 7, 33, 181, 1083, 6854, 45111, 305629, 2117283, 14929212, 106790500, 773035602, 5652275723, 41683912721, 309691336359, 2315772552485, 17415395593371, 131632335068744, 999423449413828
(list; graph; listen)
|
|
|
OFFSET
|
1,2
|
|
|
REFERENCES
|
P. Flajolet and M. Noy, Analytic Combinatorics of Noncrossing Configurations, Discrete Math. 204 (1999), 203-229.
|
|
LINKS
|
C. Banderier and D. Merlini, Lattice paths with an infinite set of jumps, FPSAC02, Melbourne, 2002.
F. Cazals, Combinatorics of Non-Crossing Configurations, Studies in Automatic Combinatorics, Volume II (1997).
Source
Philippe Flajolet, Enumeration of planar configurations in computational geometry
|
|
FORMULA
|
add(binomial(n, j - 1)*binomial(3*n - 2*j - 1, n - j)/(2*n - j), j = 1 .. n)
|
|
MAPLE
|
ZZ:=[F, {F=Union(Epsilon, ZB), ZB=Prod(Z1, P), P=Sequence(B), B=Prod(P, Z1, P), Z1=Prod(Z, F)}, unlabeled]: seq(count(ZZ, size=n), n=1..20); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Apr 22 2007
|
|
CROSSREFS
|
Cf. A006013.
Sequence in context: A067551 A080119 A055724 this_sequence A086618 A104981 A058797
Adjacent sequences: A054724 A054725 A054726 this_sequence A054728 A054729 A054730
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Philippe Flajolet (Philippe.Flajolet(AT)inria.fr), Apr 20 2000
|
|
|
Search completed in 0.002 seconds
|
