The simplify/factorial function is used to simplify expressions containing the factorial function.

$\mathrm{simplify}\left(\frac{n!}{\left(n-1\right)!}\,\mathrm{factorial}\right)$

$n$

$\mathrm{simplify}\left(n!\left(n^2+3n+2\right)\,\mathrm{factorial}\right)$

$\left(n+2\right)!$

$\mathrm{simplify}\left(\left(n+1\right)!\left(n^2+5n+6\right)\,\mathrm{factorial}\right)$

$\left(n+3\right)!$