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A052818
Number of objects generated by the Combstruct grammar defined in the Maple program. See the link for the grammar specification.
2
0, 1, 1, 3, 10, 37, 144, 593, 2515, 10975, 48847, 221071, 1013886, 4702530, 22017327, 103925505, 494000139, 2362666375, 11361442399, 54898445359, 266417109839, 1297935216161, 6345598010686, 31123068382020, 153095423135329, 755103728856195, 3733557839325332
OFFSET
0,4
LINKS
C. G. Bower, Transforms (2).
FORMULA
G.f.: x/(1-g(x)) where g(x) is the g.f. of A052815. - Andrew Howroyd, Aug 10 2020
MAPLE
spec := [S, {C=Sequence(B), B=Cycle(S), S=Prod(C, Z)}, unlabeled]: seq(combstruct[count](spec, size=n), n=0..20);
PROG
(PARI) \\ CIK (necklace, indistinct, unlabeled) in Transforms (2).
CIK(p, n)={sum(d=1, n, eulerphi(d)/d*log(subst(1/(1+O(x*x^(n\d))-p), x, x^d)))}
seq(n)={my(p=O(x)); for(n=1, n, p=x/(1-CIK(p, n))); Vec(p, -(n+1))}
CROSSREFS
Cf. A052815.
Sequence in context: A151053 A151054 A052893 * A299501 A226434 A151055
KEYWORD
easy,nonn
AUTHOR
encyclopedia(AT)pommard.inria.fr, Jan 25 2000
EXTENSIONS
Terms a(21) and beyond from Andrew Howroyd, Aug 10 2020
STATUS
approved