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Denominator of the coefficient of x^(2n+1) in the Taylor series expansion of sin(sin(x)).
3

%I #9 Jan 12 2023 06:22:58

%S 1,3,10,315,2520,49896,97297200,638512875,126309456000,47517617347200,

%T 2934911659680000,105192125402364000,1178623253808000000,

%U 1329207696584271504000000,77094046401887747232000000,10455880043256025718340000000,6973521679375808310673920000000

%N Denominator of the coefficient of x^(2n+1) in the Taylor series expansion of sin(sin(x)).

%C Numerators are A359553, see there for details.

%H Kevin Ryde, <a href="/A359554/b359554.txt">Table of n, a(n) for n = 0..220</a>

%H 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 a(n) = denominator of A003712(n)/(2n+1)!.

%o (PARI) a_vector(len) = apply(denominator, Vec(substpol(sin(sin(Ser('x,,2*len)))/'x, 'x^2,'x)));

%Y Cf. A359553 (numerators), A003712 (e.g.f. sin(sin(x))).

%K sign,frac,easy

%O 0,2

%A _Kevin Ryde_, Jan 11 2023