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 A385376 #13 Jun 27 2025 04:33:56
%S A385376 1,1,3,16,117,1104,12687,172320,2698377,47880960,949330203,
%T A385376 20801387520,499149710205,13018307696640,366673138800615,
%U A385376 11092295404707840,358685609335654545,12346621534211604480,450741642786156589875,17395372731952677519360,707614393333663454022405
%N A385376 Expansion of e.g.f. 1/(1 - 2 * arcsin(x))^(1/2).
%F A385376 a(n) = Sum_{k=0..n} A001147(k) * A385343(n,k).
%F A385376 a(n) ~ sqrt(cos(1/2)) * n^n / (exp(n) * sin(1/2)^(n + 1/2)). - _Vaclav Kotesovec_, Jun 27 2025
%o A385376 (PARI) my(N=30, x='x+O('x^N)); Vec(serlaplace(1/(1-2*asin(x))^(1/2)))
%Y A385376 Cf. A189780, A385377.
%Y A385376 Cf. A001147, A385343, A385346.
%K A385376 nonn
%O A385376 0,3
%A A385376 _Seiichi Manyama_, Jun 27 2025