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 A385471 #12 Jun 30 2025 10:04:03
%S A385471 1,3,18,168,2088,32472,605952,13192848,328268160,9189103104,
%T A385471 285808290048,9778434400512,364965976571904,14756982055363584,
%U A385471 642580290860378112,29979230177385750528,1491908801018949697536,78884742832151951278080,4416389166601900315901952
%N A385471 Expansion of e.g.f. 1/(1 - 3 * arctanh(x)).
%F A385471 E.g.f.: B(x)^3, where B(x) is the e.g.f. of A385469.
%F A385471 E.g.f.: 1/(1 - (3/2) * log((1+x)/(1-x))).
%F A385471 a(n) = Sum_{k=0..n} 3^k * k! * A111594(n,k).
%o A385471 (PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(1/(1-3*atanh(x))))
%Y A385471 Cf. A296676, A385470.
%Y A385471 Cf. A111594, A385469.
%K A385471 nonn,easy
%O A385471 0,2
%A A385471 _Seiichi Manyama_, Jun 30 2025