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 A108523 #10 Aug 31 2018 15:25:43
%S A108523 1,1,2,4,10,27,77,226,685,2112,6618,20996,67337,217884,710571,2332958,
%T A108523 7705429,25584035,85346018,285908169,961440343,3244259406,10981797187,
%U A108523 37280278698,126890974820,432950169885,1480542159038,5073504809660
%N A108523 Number of rooted identity trees with n generators.
%C A108523 A generator is a leaf or a node with just one child.
%H A108523 Andrew Howroyd, <a href="/A108523/b108523.txt">Table of n, a(n) for n = 1..200</a>
%H A108523 N. J. A. Sloane, <a href="/transforms.txt">Transforms</a>
%H A108523 <a href="/index/Ro#rooted">Index entries for sequences related to rooted trees</a>
%F A108523 G.f. satisfies (2-x)*A(x) = x - 1 + WEIGH(A(x)).
%o A108523 (PARI) WeighT(v)={Vec(exp(x*Ser(dirmul(v, vector(#v,n,(-1)^(n-1)/n))))-1,-#v)}
%o A108523 seq(n)={my(v=[1]); for(n=2, n, v=concat(v, v[#v] + WeighT(concat(v,[0]))[n])); v} \\ _Andrew Howroyd_, Aug 31 2018
%Y A108523 Cf. A108521-A108529, A004111.
%K A108523 nonn
%O A108523 1,3
%A A108523 _Christian G. Bower_, Jun 07 2005