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 A351527 #11 Feb 14 2022 03:53:42 %S A351527 1,-15,235,-4200,86020,-2001055,52305780,-1520815230,48747603100, %T A351527 -1709228504170,65115320810260,-2679459929923699,118482699493123571, %U A351527 -5604477255138004835,282449438671531808676,-15111729578894643263239 %N A351527 Expansion of e.g.f. (log(1 + log(1 + log(1 + log(1 + log(1+ x))))))^2 / 2. %F A351527 a(n) = (-1)^n * Sum_{k=1..n-1} binomial(n-1,k) * A000359(k) * A000359(n-k). %o A351527 (PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(log(1+log(1+log(1+log(1+log(1+x)))))^2/2)) %o A351527 (PARI) T(n, k) = if(k==0, n==1, sum(j=0, n, abs(stirling(n, j, 1))*T(j, k-1))); %o A351527 a(n) = (-1)^n*sum(k=1, n-1, binomial(n-1, k)*T(k, 5)*T(n-k, 5)); %Y A351527 Column 2 of A039817. %Y A351527 Cf. A000359, A341587, A351515, A351525, A351526. %K A351527 sign %O A351527 2,2 %A A351527 _Seiichi Manyama_, Feb 13 2022