Hello:

I have these two series which I can't handle:

\sum_{k=0}^\inf \frac{k^2}{k!} which according to the GRE exam is 2e. I can't see why.

The other one is:

\sum_{k=0}^\inf \frac{k}{4^(k+1)}. what is its value?

Could someone help me out?

Thanks in advance.