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 A385472 #12 Jun 30 2025 09:58:18
%S A385472 1,1,3,23,201,2529,36027,633975,12445521,282376065,7045758003,
%T A385472 196111046295,5929900611225,195773173735905,6950809317622635,
%U A385472 265652001656970615,10828342476187312545,470368564694268015105,21643209863062015977315,1053344875062427351601175
%N A385472 Expansion of e.g.f. 1/(1 - arctanh(2*x))^(1/2).
%F A385472 E.g.f.: 1/(1 - (1/2) * log((1+2*x)/(1-2*x)))^(1/2).
%F A385472 a(n) = Sum_{k=0..n} A001147(k) * 2^(n-k) * A111594(n,k).
%o A385472 (PARI) my(N=20, x='x+O('x^N)); Vec(serlaplace(1/(1-atanh(2*x))^(1/2)))
%Y A385472 Cf. A296676, A385473.
%Y A385472 Cf. A001147, A111594.
%K A385472 nonn,easy
%O A385472 0,3
%A A385472 _Seiichi Manyama_, Jun 30 2025