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 A124213 #14 Sep 08 2022 08:45:28
%S A124213 1,2,12,112,1408,22144,417216,9148416,228649472,6412193280,
%T A124213 199301663744,6798026395648,252397715738624,10131114555244544,
%U A124213 437100940892913664,20169428831476678656,991081906535967948800,51662621871173444698112,2847287574653833612623872
%N A124213 Expansion of e.g.f.: exp(exp(x)/sqrt(2-exp(2*x))-1).
%C A124213 Exponential transform of A124212.
%H A124213 G. C. Greubel, <a href="/A124213/b124213.txt">Table of n, a(n) for n = 0..380</a>
%F A124213 E.g.f.: exp(exp(x)/sqrt(2-exp(2*x))-1).
%F A124213 a(n) ~ 2^(n + 1/6) * exp(3*n^(1/3)/(2^(2/3) * log(2)^(1/3)) - n - 1) * n^(n - 1/3) / (sqrt(3) * log(2)^(n + 1/6)). - _Vaclav Kotesovec_, Jun 26 2022
%t A124213 With[{nmax = 50}, CoefficientList[Series[Exp[Exp[x]/Sqrt[2 - Exp[2*x]] - 1], {x,0,nmax}], x]*Range[0, nmax]!] (* _G. C. Greubel_, Sep 27 2018 *)
%o A124213 (PARI) x='x+O('x^30); Vec(serlaplace(exp(exp(x)/sqrt(2-exp(2*x))-1))) \\ _G. C. Greubel_, Sep 27 2018
%o A124213 (Magma) m:=30; R<x>:=PowerSeriesRing(Rationals(), m); b:=Coefficients(R!(Exp(Exp(x)/Sqrt(2-Exp(2*x))-1))); [Factorial(n-1)*b[n]: n in [1..m]]; // _G. C. Greubel_, Sep 27 2018
%Y A124213 Cf. A124212.
%K A124213 nonn
%O A124213 0,2
%A A124213 _Karol A. Penson_, Oct 19 2006