# Central value of the partial exponential function [duplicate]

I need help calculating the central value of the partial exponential function :

$$\lim_{n \to \infty} e^{-n} \sum^n_{k=0} \frac{n^k}{k!}$$

fd

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Related to a sum of independent Poisson random variables with parameter 1 –  user66322 Mar 18 '13 at 22:37