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A052829 A simple grammar. 0
0, 1, 2, 4, 10, 25, 69, 197, 583, 1762, 5441, 17042, 54072, 173334, 560659, 1827306, 5995570, 19787135, 65643226, 218777532, 732181107, 2459576149, 8290442750, 28031056619, 95045477945, 323112137130, 1101073839413, 3760472582922, 12869488098939, 44127605854574 (list; graph; refs; listen; history; text; internal format)
OFFSET

0,3

LINKS

Table of n, a(n) for n=0..29.

INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 794

FORMULA

G.f.: (x/(1-x))*Product((1+x^k)^a(k), k=1..infinity). - Vladeta Jovovic, Jul 22 2004

MAPLE

spec := [S, {B=Sequence(Z, 1 <= card), C=PowerSet(S), S=Prod(C, B)}, unlabeled]: seq(combstruct[count](spec, size=n), n=0..20);

CROSSREFS

Cf. A052870 (first differences).

Sequence in context: A191768 A027432 A032128 * A001998 A005817 A302093

Adjacent sequences:  A052826 A052827 A052828 * A052830 A052831 A052832

KEYWORD

easy,nonn

AUTHOR

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

EXTENSIONS

More terms from Alois P. Heinz, Mar 16 2016

STATUS

approved

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Last modified October 18 01:01 EDT 2018. Contains 316297 sequences. (Running on oeis4.)