Factorial Function (n!)

The factorial function ($n!$) is a recursive mathematical function that produces factorials ($5\times 4\times 3\times \dots$) of size $n$.

Definition §

$n!=n\times (n-1)!,0!=1$ For example, with 5!

$5!=5\times 4!=5\times 4\times 3!=5\times \dots 2\times =120$