I need to determine the interval of convergence of the power series

infinity

sum of series

n=1

(x+2)^n/3n5^n

I have got as far as

Here An=1/(3n5^n), for n=1,2,...

|An+1/An|=1/(3n+1)5^n+1 times 3n5^n/1

= 1/(3n+1/n)^5 ---> 1/5 as n ----> infinity.

We have R=5, by the Ratio Test. Since a=?

Can anyone help?