login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A052808 E.g.f.: -log(1-x+log(1-x)). 2

%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

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 28 05:02 EDT 2024. Contains 371235 sequences. (Running on oeis4.)