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 A383170 #11 Apr 18 2025 10:16:21
%S A383170 0,1,3,16,122,1208,14704,212336,3547984,67337728,1430990976,
%T A383170 33664165632,868592478720,24390846882816,740570519159808,
%U A383170 24177326011834368,844599686386919424,31438092340685144064,1242230898248798896128,51933512200489564962816,2290351520336982559358976
%N A383170 Expansion of e.g.f. -log(1 + log(1 - 2*x)/2).
%F A383170 a(n) = Sum_{k=1..n} 2^(n-k) * |Stirling1(n,k) * Stirling1(k,1)|.
%F A383170 a(n) ~ sqrt(Pi) * 2^(n + 1/2) * n^(n - 1/2) / (exp(1) - exp(-1))^n. - _Vaclav Kotesovec_, Apr 18 2025
%o A383170 (PARI) a(n) = sum(k=1, n, 2^(n-k)*abs(stirling(n, k, 1)*stirling(k, 1, 1)));
%Y A383170 Cf. A383171, A383172.
%Y A383170 Cf. A003713, A227917.
%K A383170 nonn
%O A383170 0,3
%A A383170 _Seiichi Manyama_, Apr 18 2025