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%I #18 Mar 11 2019 12:38:31
%S 0,2,4,-18,-856,-10950,502764,42386918,552455120,-212988964878,
%T -23803145936300,497029073217886,554580759766596984,
%U 68481112266792124458,-10157252026016020122820
%N E.g.f. tan(sin(x))*x, even numbered terms only.
%H Robert Israel, <a href="/A009667/b009667.txt">Table of n, a(n) for n = 0..250</a>
%F a(n) = 2*A024225(n). [_Martin Ettl_, Nov 08 2012]
%F a(n) = (2*n)!*[x^(2*n)] tan(sin(x))*x. - _Robert Israel_, Mar 11 2019
%p S:= series(x*tan(sin(x)),x,61):
%p seq(n!*coeff(S,x,n),n=0..60,2); # _Robert Israel_, Mar 11 2019
%t nn = 30; t = Range[0, nn]! CoefficientList[Series[Tan[Sin[x]]*x, {x, 0, nn}], x]; Take[t, {1, nn, 2}] (* _T. D. Noe_, Nov 08 2012 *)
%Y Cf. A024225.
%K sign
%O 0,2
%A _R. H. Hardin_
%E Extended with signs by _Olivier Gérard_, Mar 15 1997
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