Question

Rewrite 4n^2+2n as a factorial.

Answer 1

You can't rewrite it as a single factorial, but an expression containing several:

`4n^2+2n=2n(2n+1)=((2n+1)(2n)(2n-1)\cdots2\cdot1)/((2n-1)\cdots2\cdot1)=((2n+1)!)/((2n-1)!)`