Does the following series converge or diverge?


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    $\begingroup$ Some of the answers to your previous question from a few hours ago could be adapted to help here. For example, Cameron Buie's answer showed how you can see that $\sum \dfrac{2^n}{n!}$ converges, and the method can be adapted here, (e.g. using $n<4^n$ or the way Marvis did it). It would be appreciated by some (many, I think) if you indicate what you tried before asking. $\endgroup$ – Jonas Meyer Jun 28 '12 at 1:14

$$\sum_{n=1}^{\infty} \dfrac{4^n + n}{n!} = \sum_{n=1}^{\infty} \dfrac{4^n}{n!} + \sum_{n=1}^{\infty} \dfrac{n}{n!} = \exp(4)-1 + \sum_{n=1}^{\infty} \dfrac1{(n-1)!} = \exp(4)-1 + \exp(1)$$

  • $\begingroup$ I miss the easiest part. I didn't think about splitting it into two series! Thank you very much! $\endgroup$ – user1405177 Jun 27 '12 at 23:47

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