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.
3.9561842030261697545408021818783008332999988095...
G.f.: A(x) = 1 + x + 5*x^2 + 42*x^3 + 553*x^4 + 9757*x^5 + 213989*x^6 + 5577285*x^7 + 167819725*x^8 + 5715066723*x^9 + 217100774130*x^10 + ... such that 1 = 1/A(x) + ((1+x) - 1)/(A(x) + 1 - (1+x))^2 + ((1+x)^2 - 1)^2/(A(x) + 1 - (1+x)^2)^3 + ((1+x)^3 - 1)^3/(A(x) + 1 - (1+x)^3)^4 + ((1+x)^4 - 1)^4/(A(x) + 1 - (1+x)^4)^5 + ((1+x)^5 - 1)^5/(A(x) + 1 - (1+x)^5)^6 + ... also, 1 = 1/(A(x) + 2) + (1 + (1+x))/(A(x) + 1 + (1+x))^2 + (1 + (1+x)^2)^2/(A(x) + 1 + (1+x)^2)^3 + (1 + (1+x)^3)^3/(A(x) + 1 + (1+x)^3)^4 + (1 + (1+x)^4)^4/(A(x) + 1 + (1+x)^4)^5 + (1 + (1+x)^5)^5/(A(x) + 1 + (1+x)^5)^6 + ...
{a(n) = my(A=[1],X=x+x*O(x^n)); for(i=1,n, A=concat(A,0); A[#A] = Vec( sum(m=0, #A, ((1+X)^m - 1)^m / (Ser(A) + 1 - (1+X)^m)^(m+1) ) )[#A]); A[n+1]}
for(n=0,30,print1(a(n),", "))