Factorial moment
= Factorial moment
{wiki}
The $r$th falling factorial moment is $\mathbb{E}[(N)_r]$, where $(N)_r=N(N-1)\cdots(N-r+1)$.
= Factorial moment
{wiki}
The $r$th falling factorial moment is $\mathbb{E}[(N)_r]$, where $(N)_r=N(N-1)\cdots(N-r+1)$.