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 A356816 #14 Aug 31 2022 09:09:38
%S A356816 1,-2,-2,1,88,583,676,-35597,-519392,-3359393,19013884,896435395,
%T A356816 13640180896,85591357135,-1527872118356,-61100053650053,
%U A356816 -1076294742932288,-7610985095240513,200631806070276988,9284475508083767059,200226297062313730816,1940767272243466116463
%N A356816 Expansion of e.g.f. exp(-x * (exp(3*x) + 1)).
%H A356816 Seiichi Manyama, <a href="/A356816/b356816.txt">Table of n, a(n) for n = 0..470</a>
%F A356816 G.f.: Sum_{k>=0} (-x)^k / (1 - (3*k-1)*x)^(k+1).
%F A356816 a(n) = Sum_{k=0..n} (-1)^k * (3*k-1)^(n-k) * binomial(n,k).
%o A356816 (PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(exp(-x*(exp(3*x)+1))))
%o A356816 (PARI) my(N=30, x='x+O('x^N)); Vec(sum(k=0, N, (-x)^k/(1-(3*k-1)*x)^(k+1)))
%o A356816 (PARI) a(n) = sum(k=0, n, (-1)^k*(3*k-1)^(n-k)*binomial(n, k));
%Y A356816 Cf. A356815, A356818.
%Y A356816 Cf. A351737, A356813.
%K A356816 sign
%O A356816 0,2
%A A356816 _Seiichi Manyama_, Aug 29 2022