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 A365971 #11 Oct 30 2024 10:41:13
%S A365971 1,0,1,0,3,24,15,504,5145,9072,300321,3795120,12284811,441965160,
%T A365971 6672128463,33017539464,1306646813745,22946632267104,156924556846785,
%U A365971 6810382180903392,136393286581031571,1209571612450077240,57211108821810731151,1286884543482633415320
%N A365971 Expansion of e.g.f. exp( Sum_{k>=0} x^(3*k+2) / (3*k+2) ).
%F A365971 a(0) = 1; a(n) = (n-1)! * Sum_{k=0..floor((n-2)/3)} a(n-3*k-2)/(n-3*k-2)!.
%t A365971 nmax = 20; CoefficientList[Series[(1 + x + x^2)^(1/6) / (E^(ArcTan[Sqrt[3]*x/(2 + x)]/Sqrt[3]) * (1-x)^(1/3)), {x, 0, nmax}], x] * Range[0, nmax]! (* _Vaclav Kotesovec_, Oct 30 2024 *)
%o A365971 (PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(exp(sum(k=0, N\3, x^(3*k+2)/(3*k+2)))))
%Y A365971 Cf. A000166, A365972.
%Y A365971 Cf. A365978.
%K A365971 nonn
%O A365971 0,5
%A A365971 _Seiichi Manyama_, Sep 23 2023