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A052814
A simple grammar.
0
0, 1, 1, 2, 6, 16, 49, 156, 511, 1723, 5942, 20817, 73938, 265611, 963225, 3521667, 12966696, 48037862, 178936340, 669748197, 2517688316, 9501290664, 35982633397, 136708135198, 520914346328, 1990230295787, 7622765394301, 29262526895379, 112571409093256
OFFSET
0,4
MAPLE
spec := [S, {B=PowerSet(C), S=Prod(B, Z), C=Cycle(S)}, unlabeled]: seq(combstruct[count](spec, size=n), n=0..20);
CROSSREFS
Sequence in context: A132803 A079565 A052890 * A192401 A151445 A213429
KEYWORD
easy,nonn
AUTHOR
encyclopedia(AT)pommard.inria.fr, Jan 25 2000
EXTENSIONS
More terms from Sean A. Irvine, Dec 02 2021
STATUS
approved