[[Number theory MOC]]
# Falling factorial
The **falling factorial** is a generalization of the [[factorial]]. In Knuth's notation #m/def/num 

$$
\begin{align*}
x^{\underline n} = \prod_{k=0}^{n-1}(x-k) = x(x-1)(x-2) \cdots (x-n+1)
\end{align*}
$$


#
---
#state/develop | #lang/en | #SemBr