Convergent and divergent series?

Use the ratio test to determine whether each series is convergent or divergent.

1. (4/3)+(4/9)+(4/27)+(4/81)

2. 2+(4/2^2)+(8/3^2)+(16/4^2)

Well my issue on this problem is finding the (An) as my book calls it so that I can actually do the ration test.

for number one I know it 4/(n something but I am confused what function would express the series) I though it was (n)^3 but that wont work.

for number 2 I know it is n/n^2 but I am not sure how to represent the numerator.