I am currently reading an article, and I am a bit stuck on understanding a sentence in this article. The sentence, as indicated in the image, is: " In the case of Charlier polynomials, the measure is the Poisson distribution of probability."
Then they defined the Poisson distribution as $\frac{e^{−\mu}\mu^x}{\Gamma(x+1)}$. But what I know is that the distribution is $\frac{e^{−\mu}\mu^x}{x!}$ . Is what I said correct? Thank you in advance for your help and explanations!