

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
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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(1C(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



