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 A296678 #4 Dec 18 2017 19:43:25
%S A296678 1,3,53,2303,185033,23756667,4457821821,1150764459063,391167511473681,
%T A296678 169370797497060339,91013260219635394629,59435772666287730632559,
%U A296678 46362471059282707504957401,42577231265939498962852834155,45471686987452309473064526678925
%N A296678 Expansion of e.g.f. arctanh(arcsin(x)) (odd powers only).
%F A296678 E.g.f.: arctan(arcsinh(x)) (odd powers only, absolute values).
%F A296678 E.g.f.: log(1 - i*log(i*x + sqrt(1 - x^2)))/2 - log(1 + i*log(i*x + sqrt(1 - x^2)))/2, where i is the imaginary unit (odd powers only).
%e A296678 arctanh(arcsin(x)) = x/1! + 3*x^3/3! + 53*x^5/5! + 2303*x^7/7! + 185033*x^9/9! + 23756667*x^11/11! + ...
%t A296678 nmax = 15; Table[(CoefficientList[Series[ArcTanh[ArcSin[x]], {x, 0, 2 nmax + 1}], x] Range[0, 2 nmax + 1]!)[[n]], {n, 2, 2 nmax, 2}]
%t A296678 nmax = 15; Table[(CoefficientList[Series[Log[1 - I Log[I x + Sqrt[1 - x^2]]]/2 - Log[1 + I Log[I x + Sqrt[1 - x^2]]]/2, {x, 0, 2 nmax + 1}], x] Range[0, 2 nmax + 1]!)[[n]], {n, 2, 2 nmax, 2}]
%Y A296678 Cf. A001818, A003716, A010050, A012258, A296465, A296467, A296677.
%K A296678 nonn
%O A296678 0,2
%A A296678 _Ilya Gutkovskiy_, Dec 18 2017