OFFSET
0,3
COMMENTS
Previous name was: A simple grammar.
LINKS
INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 847
FORMULA
MAPLE
spec := [S, {B=Set(Z, 1 <= card), C=Sequence(B, 1 <= card), S=Prod(C, C)}, labeled]: seq(combstruct[count](spec, size=n), n=0..20);
MATHEMATICA
With[{nn=20}, CoefficientList[Series[((Exp[x]-1)^2/(Exp[x]-2)^2), {x, 0, nn}], x] Range[0, nn]!] (* Harvey P. Dale, Jul 19 2018 *)
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
encyclopedia(AT)pommard.inria.fr, Jan 25 2000
EXTENSIONS
Name changed by Wesley Ivan Hurt, Jun 26 2022
STATUS
approved