This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A052809 #26 Mar 11 2023 08:09:01
%S A052809 0,0,2,6,28,175,1368,12838,140656,1762794,24878320,390495336,
%T A052809 6748280064,127324033824,2604355096224,57404425654080,
%U A052809 1356401049662208,34202807058719568,916723959720053760
%N A052809 A simple grammar: number of cycles of cycles.
%H A052809 Seiichi Manyama, <a href="/A052809/b052809.txt">Table of n, a(n) for n = 0..419</a>
%H A052809 INRIA Algorithms Project, <a href="http://ecs.inria.fr/services/structure?nbr=771">Encyclopedia of Combinatorial Structures 771</a>
%F A052809 E.g.f.: log(-1/(-1+log(-1/(-1+x))))*x.
%F A052809 E.g.f.: -log(1+log(1-x))*x. - _Vaclav Kotesovec_, Oct 01 2013
%F A052809 a(n) ~ (n-1)! * (exp(1)/(exp(1)-1))^(n-1). - _Vaclav Kotesovec_, Oct 01 2013
%F A052809 a(n) = n * Sum_{k=1..n-1} (k-1)! * |Stirling1(n-1,k)| = n * A003713(n-1). - _Seiichi Manyama_, May 20 2022
%p A052809 spec := [S,{B=Cycle(C),C=Cycle(Z),S=Prod(B,Z)},labeled]: seq(combstruct[count](spec,size=n), n=0..20);
%t A052809 CoefficientList[Series[-Log[1+Log[1-x]]*x, {x, 0, 20}], x]* Range[0, 20]! (* _Vaclav Kotesovec_, Oct 01 2013 *)
%o A052809 (PARI) a(n) = n*sum(k=1, n-1, (k-1)!*abs(stirling(n-1, k, 1))); \\ _Seiichi Manyama_, May 20 2022
%Y A052809 Cf. A003713, A185393.
%K A052809 easy,nonn
%O A052809 0,3
%A A052809 encyclopedia(AT)pommard.inria.fr, Jan 25 2000