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A052853 A simple grammar. 1
0, 1, 2, 5, 14, 42, 138, 466, 1643, 5919, 21773, 81279, 307483, 1175352, 4534161, 17626999, 68992703, 271641249, 1075144364, 4275274867, 17071822275, 68428152475, 275217386092, 1110375948303, 4492641333003, 18225081419544, 74111194585752, 302040709982249 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Robert Israel, Table of n, a(n) for n = 0..1000

INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 821

FORMULA

G.f. appears to be -Sum_{j>=1} (phi(j)/j) * log(1-C(x^j)), where phi = A000010 and C is the g.f. of A050383. - Robert Israel, Nov 01 2016

MAPLE

spec := [S, {C=Prod(Z, B), S=Cycle(C), B=Set(S)}, unlabeled]: seq(combstruct[count](spec, size=n), n=0..20);

CROSSREFS

Cf. A000010, A050383.

Sequence in context: A165146 A148331 A306422 * A149877 A149878 A148332

Adjacent sequences:  A052850 A052851 A052852 * A052854 A052855 A052856

KEYWORD

easy,nonn

AUTHOR

encyclopedia(AT)pommard.inria.fr, Jan 25 2000

STATUS

approved

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Last modified November 28 20:50 EST 2020. Contains 338755 sequences. (Running on oeis4.)