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 A127130 #12 Jan 28 2020 09:00:45 %S A127130 1,4,30,284,3217,42100,621936,10206956,183946656,3608229588, %T A127130 76499111202,1742909621024,42465280193704,1101811478508828, %U A127130 30331386700718440,883010853509597608,27105284242369828508,874996700615422755068 %N A127130 Column 3 of triangle A127126. %C A127130 Self-convolution 4th power of A127133. %H A127130 G. C. Greubel, <a href="/A127130/b127130.txt">Table of n, a(n) for n = 3..80</a> %t A127130 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, 3], {n, 3, 20}] (* _G. C. Greubel_, Jan 28 2020 *) %Y A127130 Cf. A127126; A127133; other columns: A127127, A127128, A127129. %K A127130 nonn %O A127130 3,2 %A A127130 _Paul D. Hanna_, Jan 05 2007