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 A351525 #13 Jan 15 2024 17:56:37
%S A351525 1,-9,87,-975,12657,-188090,3159699,-59326371,1232843529,-28116615263,
%T A351525 698649506871,-18796044698977,544507930693022,-16903759793180115,
%U A351525 559960766050363931,-19719027513960290370,735696883534117583082,-28991986984973263419262
%N A351525 Expansion of e.g.f. (log(1 + log(1 + log(1+ x))))^2 / 2.
%F A351525 a(n) = (-1)^n * Sum_{k=1..n-1} binomial(n-1,k) * A000268(k) * A000268(n-k).
%t A351525 With[{nn=20},CoefficientList[Series[Log[1+Log[1+Log[1+x]]]^2/2,{x,0,nn}],x] Range[0,nn]!] (* _Harvey P. Dale_, Jan 15 2024 *)
%o A351525 (PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(log(1+log(1+log(1+x)))^2/2))
%o A351525 (PARI) T(n, k) = if(k==0, n==1, sum(j=0, n, abs(stirling(n, j, 1))*T(j, k-1)));
%o A351525 a(n) = (-1)^n*sum(k=1, n-1, binomial(n-1, k)*T(k, 3)*T(n-k, 3));
%Y A351525 Column 2 of A039815.
%Y A351525 Cf. A000268, A341587, A351513, A351526, A351527.
%K A351525 sign
%O A351525 2,2
%A A351525 _Seiichi Manyama_, Feb 13 2022