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 A385420 #14 Jun 28 2025 10:05:02
%S A385420 1,1,4,19,136,1849,28576,383347,6054016,162756433,4512553984,
%T A385420 94198960723,2151597168640,94600222614793,3958651982848000,
%U A385420 103976698299157747,2765446240371834880,197818347558313860385,11750108763413970288640,335351034570439348695955
%N A385420 Expansion of e.g.f. 1/(1 - arcsinh(3*x))^(1/3).
%C A385420 a(28) = -1984619795429736510626124031150165852160.
%F A385420 E.g.f.: 1/(1 - log(3*x + sqrt(9*x^2 + 1)))^(1/3).
%F A385420 a(n) = Sum_{k=0..n} A007559(k) * (3*i)^(n-k) * A385343(n,k), where i is the imaginary unit.
%o A385420 (PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(1/(1-asinh(3*x))^(1/3)))
%Y A385420 Cf. A296675, A385419.
%Y A385420 Cf. A007559, A385372, A385343, A385422.
%K A385420 sign
%O A385420 0,3
%A A385420 _Seiichi Manyama_, Jun 28 2025