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 A360815 #10 Feb 22 2023 10:19:58
%S A360815 1,0,0,1,2,3,5,11,30,88,260,771,2343,7474,25380,91650,347988,1371873,
%T A360815 5570173,23233703,99676434,440931977,2014619700,9506385864,
%U A360815 46246356169,231348803925,1187212953132,6239006165820,33546182775824,184497923546700
%N A360815 Expansion of Sum_{k>=0} x^(3*k) / (1 - k*x)^(k+1).
%F A360815 a(n) = Sum_{k=0..floor(n/3)} k^(n-3*k) * binomial(n-2*k,k).
%o A360815 (PARI) my(N=30, x='x+O('x^N)); Vec(sum(k=0, N, x^(3*k)/(1-k*x)^(k+1)))
%o A360815 (PARI) a(n) = sum(k=0, n\3, k^(n-3*k)*binomial(n-2*k, k));
%Y A360815 Cf. A360709.
%K A360815 nonn
%O A360815 0,5
%A A360815 _Seiichi Manyama_, Feb 21 2023