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A052873
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A simple grammar.
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1
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1, 1, 5, 46, 629, 11496, 263857, 7301680, 236748969, 8806142080, 369714769181, 17296339048704, 892335712777885, 50333180563864576, 3081739132775658825, 203555129140352505856, 14428195498061848405073
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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LINKS
| INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 844
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FORMULA
| E.g.f.: exp(RootOf(exp(_Z)*x*_Z+exp(_Z)*x-_Z))
1 = Sum_{n>=0} a(n)*exp((n+1)*x/(x-1))*x^n/n!. - Vladeta Jovovic (vladeta(AT)eunet.rs), Jul 20 2005
a(n) = Sum_{k=0..n} (n+1)^(k-1)*n!/k!*binomial(n-1,k-1). - Vladeta Jovovic (vladeta(AT)eunet.rs), Jul 02 2006
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MAPLE
| spec := [S, {C=Sequence(B, 1 <= card), S=Set(C), B=Prod(Z, S)}, labeled]: seq(combstruct[count](spec, size=n), n=0..20);
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CROSSREFS
| Cf. A088690.
Sequence in context: A167559 A121631 A071214 * A052894 A066998 A036246
Adjacent sequences: A052870 A052871 A052872 * A052874 A052875 A052876
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KEYWORD
| easy,nonn
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AUTHOR
| encyclopedia(AT)pommard.inria.fr, Jan 25 2000
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