%I #15 Apr 18 2017 07:04:08
%S 0,2,5,24,169,1572,18208,252676,4088138,75571648,1571427096,
%T 36304942704,922615912656,25577663099232,768176940800592,
%U 24845381066244288,860979848497650768,31825036424306681088,1249895536243141292544,51975908060575367916288
%N E.g.f.: -log(1-x+log(1-x)).
%C Previous name was: A simple grammar.
%H INRIA Algorithms Project, <a href="http://ecs.inria.fr/services/structure?nbr=770">Encyclopedia of Combinatorial Structures 770</a>
%F E.g.f.: -log(1-x+log(1-x)). - _Michael Somos_, Sep 21, 2002
%F a(n) ~ (n-1)! / (1-LambertW(1))^n. - _Vaclav Kotesovec_, Oct 01 2013
%p spec := [S,{C=Cycle(Z),B=Union(C,Z),S=Cycle(B)},labeled]: seq(combstruct[count](spec,size=n), n=0..20);
%t With[{nn=30},CoefficientList[Series[-Log[1-x+Log[1-x]],{x,0,nn}],x] Range[ 0,nn]!] (* _Harvey P. Dale_, Mar 27 2013 *)
%o (PARI) a(n)=if(n<0,0,n!*polcoeff(-log(1-x+log(1-x+x*O(x^n))),n))
%K easy,nonn
%O 0,2
%A encyclopedia(AT)pommard.inria.fr, Jan 25 2000
%E More terms from _Harvey P. Dale_, Mar 27 2013
%E New name, using e.g.f., by _Vaclav Kotesovec_, Oct 01 2013
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