Hi,

I've the following estimation:

|c_n| \leq (\log||\phi||+||a||r)\frac{2}{r^n}

where

c_n=\frac{1}{\pi i} \int_{|\lambda|=r}\log|\psi (\lambda)|\frac{d\lambda}{\lambda^{n+1}},

\phi(x+\alpha e)=\alpha

\psi(\lambda)=\phi[exp(\lambda a)].

My questions is: Why c_n=0 for n \geq 2?