- #1

The thing throwing me off is the [tex]z^{3n}[/tex]. If the series was [tex]\sum_{k=0}^\infty \frac{(n!)^3z^n}{(3n)!} [/tex] I can show it has radius of convergence of zero. But [tex]z^{3n}[/tex] means its only taking power multiples of 3. Does that change anything?

Thanks.