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 A124537 #5 Jun 14 2017 00:12:31
%S A124537 1,1,3,16,113,961,9430,104028,1267833,16866694,242836861,3758663745,
%T A124537 62200007243,1095222618881,20433071584276,402407118276836,
%U A124537 8338150233939377,181250019817152061,4122472220802095509
%N A124537 Main diagonal of rectangular table A124530.
%C A124537 In table A124530, the g.f. of row n, R_n(y), simultaneously satisfies: R_n(y) = Sum_{k>=0} y^k*R_k(y)^(n*k) for n>=0.
%o A124537 (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)))))); R[n+1][n+1]
%Y A124537 Cf. A124530 (table).
%K A124537 nonn
%O A124537 0,3
%A A124537 _Paul D. Hanna_, Nov 05 2006