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 A158108 #2 Mar 30 2012 18:37:16
%S A158108 1,1,4,21,186,1366,19433,180541,3083809,44941136,895695901,
%T A158108 11809732422,359749783368,5445775854961,140573612743254,
%U A158108 3607678852423757,119036988031104164,2273841364845589333,93765800142590570954
%N A158108 L.g.f.: exp(Sum_{n>=1} a(n)*x^n/n) = 1 + x*exp(Sum_{n>=1} sigma(n)*a(n)*x^n/n).
%F A158108 L.g.f.: exp(Sum_{n>=1} a(n)*x^n/n) = 1 + x*G(x) where G(x) = g.f. of A158107.
%o A158108 (PARI) {a(n)=local(A=x+x^2);if(n==0,1,for(i=1,n-1,A=log(1+x*exp(sum(m=1,n,sigma(m)*x^m*polcoeff(A+x*O(x^m),m) )+x*O(x^n))));n*polcoeff(A,n))}
%Y A158108 Cf. A158107.
%K A158108 nonn
%O A158108 1,3
%A A158108 _Paul D. Hanna_, Mar 28 2009