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 A351513 #14 Feb 13 2022 06:33:37
%S A351513 1,9,75,660,6288,65051,728556,8792910,113805204,1572387410,
%T A351513 23094192960,359209182397,5896792771795,101854538628396,
%U A351513 1846058978130172,35021271971160507,693843099578350329,14326635965967487711,307729547549467823822,6864250658908517748384
%N A351513 Expansion of e.g.f. (exp(exp(exp(x)-1)-1)-1)^2 / 2.
%F A351513 a(n) = Sum_{k=1..n-1} binomial(n-1,k) * A000258(k) * A000258(n-k).
%o A351513 (PARI) my(N=40, x='x+O('x^N)); Vec(serlaplace((exp(exp(exp(x)-1)-1)-1)^2/2))
%o A351513 (PARI) T(n, k) = if(k==0, n<=1, sum(j=0, n, stirling(n, j, 2)*T(j, k-1)));
%o A351513 a(n) = sum(k=1, n-1, binomial(n-1, k)*T(k, 3)*T(n-k, 3));
%Y A351513 Column 2 of A039811.
%Y A351513 Cf. A000258, A000558, A351514, A351515.
%K A351513 nonn
%O A351513 2,2
%A A351513 _Seiichi Manyama_, Feb 12 2022