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%I #20 Feb 19 2018 18:13:38
%S 1,7,117,4555,317577,34316335,5287957053,1099518892339,
%T 296443784525713,100546719214082775,41891900484967019141,
%U 21030561862406486561563,12519930918307503306140953
%N Expansion of tan(tan(x))*cosh(x) (odd powers only).
%H Robert Israel, <a href="/A009696/b009696.txt">Table of n, a(n) for n = 1..225</a>
%F a(n) ~ (2*n-1)! * 8 * cosh(arctan(Pi/2)) / ((4+Pi^2) * arctan(Pi/2)^(2*n)). - _Vaclav Kotesovec_, Jan 23 2015
%p S:= series(tan(tan(x))*cosh(x), x, 40):
%p seq(coeff(S,x,j)*j!, j=1..39,2); # _Robert Israel_, Feb 19 2018
%t Tan[ Tan[ x ]]*Cosh[ x ] (* Odd Part *)
%t nn = 20; Table[(CoefficientList[Series[Cosh[x]*Tan[Tan[x]], {x, 0, 2*nn+1}], x] * Range[0, 2*nn+1]!)[[n]], {n, 2, 2*nn, 2}] (* _Vaclav Kotesovec_, Jan 23 2015 *)
%K nonn
%O 1,2
%A _R. H. Hardin_
%E Extended and signs tested by _Olivier Gérard_, Mar 15 1997
%E Offset changed to 1 by _Vaclav Kotesovec_, Jan 23 2015
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