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 A349116 #9 Nov 08 2021 09:10:41
%S A349116 1,7,57,605,7990,126378,2331462,49183590,1168343775,30871159429,
%T A349116 898302280271,28547663567787,983905660878140,36556999252315556,
%U A349116 1456715662183096092,61973464872507939132,2803744852868605501965,134413716665674685292183,6807005707226954237422477
%N A349116 a(n) = Sum_{m=1..n} (Sum_{k=1..m} (Sum_{j=1..k} j^n)).
%H A349116 Vaclav Kotesovec, <a href="/A349116/b349116.txt">Table of n, a(n) for n = 1..200</a>
%F A349116 a(n) ~ c * n^n, where c = 1/(1 - 3/exp(1) + 3/exp(2) - 1/exp(3)) = 3.959134481...
%t A349116 Table[Sum[Sum[Sum[j^n, {j, 1, k}], {k, 1, m}], {m, 1, n}], {n, 1, 20}]
%Y A349116 Cf. A215084, A349117.
%K A349116 nonn
%O A349116 1,2
%A A349116 _Vaclav Kotesovec_, Nov 08 2021