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n-th derivative of cos(x)^tan(x) at x=0.
2

%I #7 Aug 20 2012 17:07:08

%S 1,0,0,-3,0,-30,90,-588,5040,-26520,325080,-2158728,27731880,

%T -249259920,3181258080,-36821629848,482278043520,-6704476956480,

%U 93675256079040,-1479108131816448,22566722722104960,-390679249452835200,6559255213047250560,-122197022127873558528

%N n-th derivative of cos(x)^tan(x) at x=0.

%F E.g.f.: cos(x)^tan(x).

%p a:= n-> n!* coeff(series(cos(x)^tan(x), x, n+1), x, n):

%p seq (a(n), n=0..25);

%t f[x_] := Cos[x]^Tan[x]; Table[Derivative[ n] [f][0],{n,0,25}]

%Y Cf. A215588, A215680.

%K sign

%O 0,4

%A _Michel Lagneau_, Aug 16 2012