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 A359554 #9 Jan 12 2023 06:22:58
%S A359554 1,3,10,315,2520,49896,97297200,638512875,126309456000,47517617347200,
%T A359554 2934911659680000,105192125402364000,1178623253808000000,
%U A359554 1329207696584271504000000,77094046401887747232000000,10455880043256025718340000000,6973521679375808310673920000000
%N A359554 Denominator of the coefficient of x^(2n+1) in the Taylor series expansion of sin(sin(x)).
%C A359554 Numerators are A359553, see there for details.
%H A359554 Kevin Ryde, <a href="/A359554/b359554.txt">Table of n, a(n) for n = 0..220</a>
%H A359554 Christopher Towse, <a href="https://www.jstor.org/stable/10.4169/math.mag.87.5.338">Iteration of Sine and Related Power Series</a>, Mathematics Magazine, volume 87, number 5, December 2014, pages 338-349.
%F A359554 a(n) = denominator of A003712(n)/(2n+1)!.
%o A359554 (PARI) a_vector(len) = apply(denominator, Vec(substpol(sin(sin(Ser('x,,2*len)))/'x, 'x^2,'x)));
%Y A359554 Cf. A359553 (numerators), A003712 (e.g.f. sin(sin(x))).
%K A359554 sign,frac,easy
%O A359554 0,2
%A A359554 _Kevin Ryde_, Jan 11 2023