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Denominators of expansion of exp x / sin x.
3

%I #13 Jul 14 2024 16:15:32

%S 1,3,3,90,18,945,1890,12600,22680,53460,1247400,10216206000,157172400,

%T 1021620600,6129723600,534386160000,81729648000,2494674910728000,

%U 127932046704000,2744142401800800000

%N Denominators of expansion of exp x / sin x.

%H Robert Israel, <a href="/A007451/b007451.txt">Table of n, a(n) for n = 0..70</a>

%p c:= proc(m) option remember;

%p 1/(m+1)! - add((-1)^i/(2*i+1)!*c(m-2*i),i=1..floor((m+1)/2))

%p end proc;

%p c(-1):= 1;

%p A007451:= denom @ c; # _Robert Israel_, Apr 13 2014

%t Denominator[CoefficientList[Series[Exp[x]/Sin[x],{x,0,20}],x]]//Quiet (* _Harvey P. Dale_, Mar 16 2018 *)

%Y Cf. A007418.

%K nonn,frac

%O 0,2

%A _N. J. A. Sloane_.