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 A124547 #5 Jun 14 2017 00:13:20
%S A124547 1,1,7,73,939,13976,233241,4282895,85445683,1834958107,42110641373,
%T A124547 1026677317227,26462793170760,718141884712500,20446913056248836,
%U A124547 608923223179959780,18917094810892717955,611616504412815339432
%N A124547 Main diagonal of rectangular table A124540.
%C A124547 In table A124540, the g.f. of row n, R_n(y), simultaneously satisfies: R_n(y) = [ Sum_{k>=0} y^k*R_k(y)^n ]^n for n>=0.
%o A124547 (PARI) a(n)=local(R);R=vector(n+1,r,vector(n+1,c,if(r==1 || c<=2,1,r^(c-2)))); for(i=0,n,for(r=0,n,R[r+1]=Vec(sum(c=0,n,x^c*Ser(R[c+1])^(r*c)+O(x^(n+1)))))); Vec(Ser(R[n+1])^n+O(x^(n+1)))[n+1]
%Y A124547 Cf. A124540, A124548, A124549.
%K A124547 nonn
%O A124547 0,3
%A A124547 _Paul D. Hanna_, Nov 05 2006