|
| |
|
|
A052828
|
|
A simple grammar: union of cycles and cycles of cycles.
|
|
0
| |
|
|
0, 2, 3, 9, 41, 252, 1954, 18302, 200906, 2528152, 35862456, 565985472, 9834073248, 186504365616, 3833188731072, 84862243895088, 2013237501351504, 50950031663224320, 1370088133344414336
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 0,2
|
|
|
LINKS
| INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 793
|
|
|
FORMULA
| E.g.f.: ln(-1/(-1+x))+ln(-1/(-1+ln(-1/(-1+x))))
|
|
|
MAPLE
| Union spec := [S, {B=Cycle(C), C=Cycle(Z), S=Union(C, B)}, labeled]: seq(combstruct[count](spec, size=n), n=0..20);
|
|
|
CROSSREFS
| Sequence in context: A125052 A181139 A162093 * A012972 A162094 A162095
Adjacent sequences: A052825 A052826 A052827 * A052829 A052830 A052831
|
|
|
KEYWORD
| easy,nonn
|
|
|
AUTHOR
| encyclopedia(AT)pommard.inria.fr, Jan 25 2000
|
| |
|
|
