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 A159308 #2 Mar 30 2012 18:37:17
%S A159308 1,1,2,5,14,40,154,631,2246,10476,71232,383220,1553841,8223567,
%T A159308 58756725,338290401,1754330940,11744499990,103864469131,1220564280222,
%U A159308 17394859369497,214311637862464,1891506713163679,10894997683415647
%N A159308 G.f.: A(x) = exp( Sum_{n>=1} (1 + sigma(n)*x)^n * x^n/n ).
%e A159308 G.f.: A(x) = 1 + x + 2*x^2 + 5*x^3 + 14*x^4 + 40*x^5 + 154*x^6 +...
%e A159308 log(A(x)) = (1+x)*x + (1+3*x)^2*x^2/2 + (1+4*x)^3*x^3/3 + (1+7*x)^4*x^4/4 +...
%e A159308 log(A(x)) = x + 3*x^2/2 + 10*x^3/3 + 35*x^4/4 + 116*x^5/5 + 606*x^6/6 +... (A159309)
%o A159308 (PARI) {a(n)=polcoeff(exp(sum(m=1,n+1,(1+sigma(m)*x+x*O(x^n))^m*x^m/m)),n)}
%Y A159308 Cf. A159309 (log).
%K A159308 nonn
%O A159308 0,3
%A A159308 _Paul D. Hanna_, Apr 10 2009