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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
Sequence in context: A186942 A193913 A292097 * A137957 A002514 A319216
KEYWORD
easy,nonn
AUTHOR
encyclopedia(AT)pommard.inria.fr, Jan 25 2000
EXTENSIONS
New name from Ilya Gutkovskiy, May 26 2023
STATUS
approved

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Last modified March 28 05:39 EDT 2024. Contains 371235 sequences. (Running on oeis4.)