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 A349874 #6 Dec 03 2021 09:56:40
%S A349874 1,3,15,106,990,11688,168529,2886039,57372984,1299676869,33049616319,
%T A349874 931991169660,28856822050546,972979199567826,35480222492288493,
%U A349874 1391109691131953417,58351612093156552572,2607190821521732751855,123613763047459102476027
%N A349874 Expansion of A(x)^3, where A(x) is g.f. of n^n (A000312).
%F A349874 a(n) ~ 3 * n^n.
%t A349874 nmax = 20; CoefficientList[Series[(1 + Sum[n^n * x^n, {n,1,nmax}])^3, {x,0,nmax}],x]
%Y A349874 Cf. A000312, A053729, A100262.
%K A349874 nonn
%O A349874 0,2
%A A349874 _Vaclav Kotesovec_, Dec 03 2021