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 + 2*x^2 + 12*x^3 + 200*x^4 + 4160*x^5 + 99862*x^6 + 2767792*x^7 + 87200166*x^8 + 3076185774*x^9 + 120118928740*x^10 + ... such that A = A(x) satisfies A(x) = 1/(2 - A) + ((1+x) - A)/(2 - (1+x)*A)^2 + ((1+x)^2 - A)^2/(2 - (1+x)^2*A)^3 + ((1+x)^3 - A)^3/(2 - (1+x)^3*A)^4 + ((1+x)^4 - A)^4/(2 - (1+x)^4*A)^5 + ((1+x)^5 - A)^5/(2 - (1+x)^5*A)^6 + ... Also, A(x) = 1/(2 + A) + ((1+x) + A)/(2 + (1+x)*A)^2 + ((1+x)^2 + A)^2/(2 + (1+x)^2*A)^3 + ((1+x)^3 + A)^3/(2 + (1+x)^3*A)^4 + ((1+x)^4 + A)^4/(2 + (1+x)^4*A)^5 + ((1+x)^5 + A)^5/(2 + (1+x)^5*A)^6 + ...
{a(n) = my(A=[1]); for(i=1,n, A=concat(A,0); A = Vec( sum(m=0,#A, ( (1+x)^m - Ser(A) )^m / (2 - (1+x)^m*Ser(A))^(m+1) ) ) ); A[n+1]}
for(n=0,30,print1(a(n),", "))
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