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 A352945 #18 Oct 30 2022 08:57:12
%S A352945 1,0,0,1,1,1,2,3,5,10,20,42,93,214,516,1307,3473,9659,28002,84257,
%T A352945 262229,842196,2787864,9506796,33388393,120727844,449148808,
%U A352945 1717595949,6743420017,27147152525,111931584098,472225684599,2037019695797,8979468552886,40432306870108
%N A352945 a(n) = Sum_{k=0..floor(n/3)} k^(n-3*k).
%H A352945 Seiichi Manyama, <a href="/A352945/b352945.txt">Table of n, a(n) for n = 0..738</a>
%F A352945 G.f.: Sum_{k>=0} x^(3*k) / (1 - k * x).
%F A352945 a(n) ~ sqrt(2*Pi/3) * (n/(3*LambertW(exp(1)*n/3)))^(n + 1/2 - n/LambertW(exp(1)*n/3)) / sqrt(1 + LambertW(exp(1)*n/3)). - _Vaclav Kotesovec_, Apr 14 2022
%o A352945 (PARI) a(n) = sum(k=0, n\3, k^(n-3*k));
%o A352945 (PARI) my(N=40, x='x+O('x^N)); Vec(sum(k=0, N, x^(3*k)/(1-k*x)))
%Y A352945 Cf. A104872, A355575.
%K A352945 nonn,easy
%O A352945 0,7
%A A352945 _Seiichi Manyama_, Apr 09 2022