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 A179467 #5 Mar 30 2012 18:37:22 %S A179467 1,1,3,7,19,47,131,351,992,2808,8131,23723,70192,209209,629165, %T A179467 1904391,5801109,17764063,54663309,168925259,524064687,1631511342, %U A179467 5095440198,15960070908,50124189982,157806721089,497953049736,1574573746276 %N A179467 G.f. satisfies: A(x) = exp( Sum_{n>=1} sigma(n)*A(x^n)*x^n/n ). %F A179467 G.f.: Sum_{n>=0} a(n)*x^n = Product_{n>=1} P(x^n)^a(n-1) where P(x) = Product_{k>=1} 1/(1-x^k) is the partition function. %e A179467 G.f.: A(x) = 1 + x + 3*x^2 + 7*x^3 + 19*x^4 + 47*x^5 + 131*x^6 +... %e A179467 log(A(x)) = A(x)*x + 3*A(x^2)*x^2/2 + 4*A(x^3)*x^3/3 + 7*A(x^4)*x^4/4 +... %o A179467 (PARI) {a(n)=local(A=1+x);for(i=1,n,A=exp(sum(m=1,n,subst(A,x,x^m+x*O(x^n))*sigma(m)*x^m/m)));polcoeff(A,n)} %o A179467 (PARI) {a(n)=if(n<0,0,if(n==0,1,polcoeff(1/prod(m=1,n,prod(k=1,n\m+1,1-x^(k*m)+x*O(x^n))^a(m-1)),n)))} %K A179467 nonn %O A179467 0,3 %A A179467 _Paul D. Hanna_, Jul 15 2010