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 A360813 #9 Feb 22 2023 10:20:21
%S A360813 1,1,1,1,2,17,82,258,818,5671,43363,240520,1183168,8547054,77831681,
%T A360813 596258173,4031934111,33313129161,338733239446,3187239159511,
%U A360813 27197807726066,260179611473044,2918973182685904,31820249821418229,324099587971865989
%N A360813 Expansion of Sum_{k>=0} ( x / (1 - (k * x)^3) )^k.
%F A360813 a(n) = Sum_{k=0..floor(n/3)} (n-3*k)^(3*k) * binomial(n-2*k-1,k).
%o A360813 (PARI) my(N=30, x='x+O('x^N)); Vec(sum(k=0, N, (x/(1-(k*x)^3))^k))
%o A360813 (PARI) a(n) = sum(k=0, n\3, (n-3*k)^(3*k)*binomial(n-2*k-1, k));
%Y A360813 Cf. A339481, A360788.
%K A360813 nonn
%O A360813 0,5
%A A360813 _Seiichi Manyama_, Feb 21 2023