Derivatives of PGF of Negative Binomial Distribution/Second Form

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Let $X$ be a discrete random variable with the negative binomial distribution (second form) with parameters $n$ and $p$.

Then the derivatives of the PGF of $X$ with respect to $s$ are:

$\dfrac {\d^k} {\d s^k} \map {\Pi_X} s = ...$


The Probability Generating Function of Negative Binomial Distribution (Second Form) is:

$\map {\Pi_X} s = \paren {\dfrac {p s} {1 - q s} }^n$

We have that for a given negative binomial distribution , $n, p$ and $q$ are constant.