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 A060905 #32 Oct 31 2024 22:27:38
%S A060905 1,1,4,19,110,751,5902,52165,509588,5437729,62828306,780287839,
%T A060905 10351912276,145944541159,2176931651546,34225419288421,
%U A060905 565282627986368,9779830102138945,176776613812205074,3330780287838743575
%N A060905 Expansion of e.g.f. exp(x*exp(x) + 1/2*x^2*exp(x)^2).
%C A060905 Number of functions f from a set of size n to itself such that f(f(f(x))) = f(x). - _Joel B. Lewis_, Dec 12 2011
%D A060905 I. P. Goulden and D. M. Jackson, Combinatorial Enumeration, Wiley, N.Y., 1983.
%H A060905 Alois P. Heinz, <a href="/A060905/b060905.txt">Table of n, a(n) for n = 0..200</a>
%H A060905 Vladimir Kruchinin, <a href="http://arxiv.org/abs/1009.2565">Composition of ordinary generating functions</a>, arXiv:1009.2565 [math.CO], 2010.
%F A060905 E.g.f.: exp(Sum_{d|m} T_k^d/d), where T_k = x*exp(T_(k - 1)), k >= 1, T_0 = x; k = 1, m = 2.
%F A060905 a(n) = sum(sum(k^(n-k)/(n-k)!*binomial(m,k-m)*(1/2)^(k-m),k,m,n)/m!,m,1,n), n>0. - _Vladimir Kruchinin_, Aug 20 2010
%t A060905 nn=20;a=x Exp[x];Range[0,nn]!CoefficientList[Series[Exp[a+a^2/2],{x,0,nn}],x] (* _Geoffrey Critzer_, Sep 18 2012 *)
%o A060905 (Maxima) a(n):=sum(sum(k^(n-k)/(n-k)!*binomial(m,k-m)*(1/2)^(k-m),k,m,n)/m!,m,1,n); /* _Vladimir Kruchinin_, Aug 20 2010 */
%Y A060905 Cf. A000949 - A000951, A060905 - A060913.
%Y A060905 Column k=3 of A245501.
%K A060905 nonn
%O A060905 0,3
%A A060905 _Vladeta Jovovic_, Apr 07 2001