Original question: Is there any way to write $x!$ as a Pi notation? $$x!=\prod\text{?}$$
The answer should have been obvious $$x!=\prod_{r=1}^xr$$
Now I have an additional question:
Is it possible to write $\left(2(\ x+1 )\ \right)!$ as a product notation? $$(2(x+1))!=\prod?$$
You can write like this:
$$x!=\prod_{r=1}^x\text{r}$$
For additional question:
$$(2x+2)!=\prod_{r=1}^{(2x+2)}\text{r}$$