|
|
A052755
|
|
G.f. A(x) satisfies: A(x) = exp( Sum_{k>=1} (-1)^(k+1) * A(x^k)^3 * x^k / k )
|
|
3
|
|
|
1, 1, 3, 15, 79, 466, 2872, 18409, 121197, 815491, 5581214, 38737651, 272012178, 1928939678, 13794498614, 99371002295, 720411445866, 5252194141946, 38482834469488, 283223825607253, 2092829973445703
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
0,3
|
|
COMMENTS
|
Old name was: A simple grammar.
|
|
LINKS
|
|
|
FORMULA
|
G.f. A(x) satisfies: A(x) = exp( Sum_{k>=1} (-1)^(k+1) * A(x^k)^3 * x^k / k ). - Ilya Gutkovskiy, May 26 2023
|
|
MAPLE
|
spec := [S, {S=PowerSet(B), B=Prod(S, S, S, Z)}, unlabeled]: seq(combstruct[count](spec, size=n), n=0..20);
|
|
CROSSREFS
|
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
encyclopedia(AT)pommard.inria.fr, Jan 25 2000
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|