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 A360817 #14 Jan 09 2024 08:46:29
%S A360817 1,0,0,1,2,3,68,389,1542,24810,251564,1814487,27520734,391640548,
%T A360817 4295115396,69305652406,1221344986380,18207710383335,329699350020676,
%U A360817 6759819628538561,126950556666301050,2624697847966227077,60825028694289947940,1365568620213461601924
%N A360817 Expansion of Sum_{k>=0} (k*x)^(3*k) / (1 - k*x)^(k+1).
%H A360817 Seiichi Manyama, <a href="/A360817/b360817.txt">Table of n, a(n) for n = 0..449</a>
%F A360817 a(n) = Sum_{k=0..floor(n/3)} k^n * binomial(n-2*k,k).
%o A360817 (PARI) my(N=30, x='x+O('x^N)); Vec(sum(k=0, N, (k*x)^(3*k)/(1-k*x)^(k+1)))
%o A360817 (PARI) a(n) = sum(k=0, n\3, k^n*binomial(n-2*k, k));
%Y A360817 Cf. A072034, A360816.
%Y A360817 Cf. A360815.
%K A360817 nonn
%O A360817 0,5
%A A360817 _Seiichi Manyama_, Feb 21 2023