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Expansion of e.g.f. sin(x)^2 * sinh(x)^2.
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%I #18 Mar 19 2023 03:35:33

%S 24,-896,67584,-4161536,268959744,-17171480576,1099645845504,

%T -70366596694016,4503633987108864,-288229826395897856,

%U 18446752869802573824,-1180591479979922948096,75557865977714137104384

%N Expansion of e.g.f. sin(x)^2 * sinh(x)^2.

%C The sequence contains each 4th term of the e.g.f. sin(x)^2*sinh(x)^2 = (24/4!)*x^4 - (896/8!)*x^8 + (67584/12!)*x^12 + ... - _R. J. Mathar_, Dec 17 2017

%H <a href="/index/Rec#order_02">Index entries for linear recurrences with constant coefficients</a>, signature (-48,1024).

%F a(n) = (1/2)*16^n - (1/4)*(-64)^n. [Corrected by _Delbert L. Johnson_, Mar 11 2023]

%F G.f.: 8*x*(3+32*x)/((1-16*x)*(1+64*x)).

%K sign,easy

%O 1,1

%A _Ralf Stephan_, May 25 2005