A052835 E.g.f.: 1/(1+log(1-x))-log(1-x).

1, 2, 4, 16, 94, 718, 6698, 73512, 925944, 13149408, 207723792, 3611861856, 68535403440, 1409110979664, 31203828680880, 740391021216384, 18739539315968256, 503958517859488896, 14350254992824182912, 431329037106221865216, 13646963521734433991424

Offset

0,2

Comments

Previous name was: A simple grammar.

Links

Table of n, a(n) for n=0..20.

INRIA Algorithms Project, Encyclopedia of Combinatorial Structures 802

Formula

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

a(n) ~ n! * exp(n)/(exp(1)-1)^(n+1). - Vaclav Kotesovec, Sep 30 2013

Maple

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

Mathematica

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

Crossrefs

Sequence in context: A058136 A156335 A026089 * A009565 A009838 A088335

Adjacent sequences: A052832 A052833 A052834 * A052836 A052837 A052838

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

More terms from Alois P. Heinz, Mar 16 2016

Status

approved