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A052891
Number of objects generated by the Combstruct grammar defined in the Maple program. See the link for the grammar specification.
2
0, 1, 2, 5, 16, 56, 217, 876, 3686, 15903, 70103, 314042, 1426076, 6548060, 30352695, 141837086, 667469159, 3160370217, 15045244375, 71970393570, 345766441537, 1667629158127, 8071308125136, 39190243658297, 190845259909328, 931856232714004, 4561292365652751
OFFSET
0,3
LINKS
FORMULA
G.f.: 1 - 1/g(x) where g(x) is the g.f. of A052893. - Andrew Howroyd, Aug 09 2020
MAPLE
spec := [S, {C=Prod(Z, B), S=Set(C, 1 <= card), B=Sequence(S)}, unlabeled]:
seq(combstruct[count](spec, size=n), n=0..20);
PROG
(PARI) EulerT(v)={Vec(exp(x*Ser(dirmul(v, vector(#v, n, 1/n))))-1, -#v)}
seq(n)={my(v=[0]); for(n=1, n, v=concat([0], EulerT(Vec(1/(1-Ser(v)))))); v} \\ Andrew Howroyd, Aug 09 2020
CROSSREFS
Cf. A052893.
Sequence in context: A141201 A149977 A147771 * A352905 A052815 A195931
KEYWORD
easy,nonn
AUTHOR
encyclopedia(AT)pommard.inria.fr, Jan 25 2000
EXTENSIONS
Terms a(21) and beyond from Andrew Howroyd, Aug 09 2020
STATUS
approved