A052846 E.g.f.: (1-exp(x))*log(2-exp(x)).

0, 0, 2, 9, 40, 215, 1446, 11893, 115844, 1302099, 16568290, 235237937, 3684998208, 63113398543, 1173013230494, 23509415868141, 505358483764732, 11597234229683147, 282970077651917658, 7314780938223880105

Offset

0,3

Comments

Previous name was: A simple grammar.

Links

Table of n, a(n) for n=0..19.

INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 814

Formula

E.g.f.: log(-1/(-2+exp(x)))*exp(x)-log(-1/(-2+exp(x)))

a(n) ~ (n-1)! / log(2)^n. - Vaclav Kotesovec, Sep 30 2013

Maple

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

Mathematica

CoefficientList[Series[(1-E^x) * Log[2-E^x], {x, 0, 20}], x]* Range[0, 20]! (* Vaclav Kotesovec, Sep 30 2013 *)

Crossrefs

Sequence in context: A038156 A296964 A261047 * A293152 A327827 A056844

Adjacent sequences: A052843 A052844 A052845 * A052847 A052848 A052849

Keyword

easy,nonn

Author

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

Extensions

New name, using e.g.f., by Vaclav Kotesovec, Sep 30 2013

Status

approved