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 A012248 #16 Nov 02 2020 11:07:05
%S A012248 1,1,1,1,1,9,49,225,897,11025,96801,893025,6803457,108056025,
%T A012248 1275363153,18261468225,207592347393,4108830350625,60889593787713,
%U A012248 1187451971330625,17888210916886017,428670161650355625,7679611833095218545,189043541287806830625,3530100224793651058305
%N A012248 Expansion of e.g.f. exp(arcsinh(arcsin(x))).
%F A012248 E.g.f.: Q(0)-1, where Q(k) = 2 + arcsin(x)/(1 - arcsin(x)/Q(k+1) ); (continued fraction). - _Sergei N. Gladkovskii_, Dec 19 2013
%e A012248 1 + x + 1/2!*x^2 + 1/3!*x^3 + 1/4!*x^4 + 9/5!*x^5...
%t A012248 With[{nn=25},CoefficientList[Series[Exp[ArcSinh[ArcSin[x]]],{x,0,nn}],x] Range[ 0,nn]!] (* _Harvey P. Dale_, Nov 02 2020 *)
%o A012248 (PARI) x = 'x + O('x^30); Vec(serlaplace(exp(asinh(asin(x))))) \\ _Michel Marcus_, Mar 09 2017
%Y A012248 Bisections are |A012115(n)| and A001818.
%K A012248 nonn
%O A012248 0,6
%A A012248 Patrick Demichel (patrick.demichel(AT)hp.com)
%E A012248 More terms from _Michel Marcus_, Mar 09 2017