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 A127129 #10 Jan 28 2020 12:08:24
%S A127129 1,3,18,139,1314,14658,188012,2721462,43837014,777266691,15037898091,
%T A127129 315177210360,7112634073455,171930274269408,4431595775955999,
%U A127129 121321383915646543,3515347574087951331,107474295428549047272
%N A127129 Column 2 of triangle A127126.
%C A127129 Self-convolution cube of A127132.
%H A127129 G. C. Greubel, <a href="/A127129/b127129.txt">Table of n, a(n) for n = 2..80</a>
%t A127129 T[n_, k_]:= T[n, k]= If[k==n, 1, Coefficient[(1 +x*Sum[x^(r-k-1)*Sum[T[r, c], {c,k+1,r}], {r,k+1,n}] + x^(n+1))^(k+1), x, n-k]]; Table[T[n, 2], {n, 2, 20}] (* _G. C. Greubel_, Jan 28 2020 *)
%Y A127129 Cf. A127126; A127132; other columns: A127127, A127128, A127130.
%K A127129 nonn
%O A127129 2,2
%A A127129 _Paul D. Hanna_, Jan 05 2007