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 A353017 #12 Apr 16 2022 09:39:28
%S A353017 1,1,1,1,2,9,28,66,190,946,4441,16650,67069,380795,2220697,11142307,
%T A353017 58133022,380165427,2581541092,15919859932,101602799146,758173118356,
%U A353017 5826902270129,42158185020684,316416126945385,2656178496077301,22725296418141937,187568834724460765
%N A353017 a(n) = Sum_{k=0..floor(n/3)} (n-3*k)^(3*k).
%F A353017 G.f.: Sum_{k>=0} x^k / (1 - (k * x)^3).
%t A353017 a[0] = 1; a[n_] := Sum[(n-3*k)^(3*k), {k, 0, Floor[n/3]}]; Array[a, 30, 0] (* _Amiram Eldar_, Apr 16 2022 *)
%o A353017 (PARI) a(n) = sum(k=0, n\3, (n-3*k)^(3*k));
%o A353017 (PARI) my(N=40, x='x+O('x^N)); Vec(sum(k=0, N, x^k/(1-(k*x)^3)))
%Y A353017 Cf. A352946, A353015.
%K A353017 nonn,easy
%O A353017 0,5
%A A353017 _Seiichi Manyama_, Apr 16 2022