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 A377692 #20 Aug 27 2025 04:18:49
%S A377692 1,2,12,118,1634,29408,654040,17362056,536410200,18922946928,
%T A377692 750902659200,33118793900784,1607673329621712,85192554602094912,
%U A377692 4894219487974911552,303021216528999244416,20116223556200658052992,1425479651299747192856832,107400336067263661850548224
%N A377692 E.g.f. satisfies A(x) = (1 - log(1 - x) * A(x))^2.
%F A377692 E.g.f.: 4/(1 + sqrt(1 + 4*log(1-x)))^2.
%F A377692 E.g.f.: B(x)^2, where B(x) is the e.g.f. of A052803.
%F A377692 a(n) = 2 * Sum_{k=0..n} (2*k+1)!/(k+2)! * |Stirling1(n,k)|.
%F A377692 a(n) ~ 2^(7/2) * n^(n-1) / ((exp(1/4) - 1)^(n - 1/2) * exp(3*n/4)). - _Vaclav Kotesovec_, Aug 27 2025
%o A377692 (PARI) a(n) = 2*sum(k=0, n, (2*k+1)!/(k+2)!*abs(stirling(n, k, 1)));
%Y A377692 Cf. A007840, A377693.
%Y A377692 Cf. A052803, A377445.
%K A377692 nonn,changed
%O A377692 0,2
%A A377692 _Seiichi Manyama_, Nov 04 2024