login
E.g.f.: exp(x)-1+log(-1/(-2+exp(x))).
0

%I #17 Apr 18 2017 07:04:12

%S 0,2,3,7,27,151,1083,9367,94587,1091671,14174523,204495127,3245265147,

%T 56183135191,1053716696763,21282685940887,460566381955707,

%U 10631309363962711,260741534058271803,6771069326513690647

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

%C Previous name was: A simple grammar.

%H INRIA Algorithms Project, <a href="http://ecs.inria.fr/services/structure?nbr=848">Encyclopedia of Combinatorial Structures 848</a>

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

%F a(n) ~ (n-1)! / log(2)^n. - _Vaclav Kotesovec_, Sep 30 2013

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

%t CoefficientList[Series[E^x-1+Log[-1/(-2+E^x)], {x, 0, 20}], x]* Range[0, 20]! (* _Vaclav Kotesovec_, Sep 30 2013 *)

%Y a(n) = A000629(n-1)+1, n>0. Cf. A002050.

%K easy,nonn

%O 0,2

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

%E New name, using e.g.f., from _Vaclav Kotesovec_, Sep 30 2013