A memory chip from a microcomputer has $\displaystyle 2^4$ bistable (ON-OFF) memory elements. What is the total number of ON-OFF configurations?

I have no idea where to start here. The book says:

$\displaystyle 2^{2^2} = 2^{16}$

Or something along those lines, the $\displaystyle 2^{16}$ is there, but I'm not sure that that's how they arranged the twos, either way, it confuses me.

Should it be:

$\displaystyle 2^{4^2} = 2^{16}$?