Notation for powers of a limit?

Question

I was trying to find the conventional notation for taking a limit to a power. e.g. for the square of the limit of $f(x)$ as $x$ approaches $a$, is $${\lim_{x\to a}}^2f(x)$$ acceptable? Or would it be better to use the clearer $$\left[\lim_{x\to a}f(x)\right]^2$$? Thanks in advance.

Answer 1

CW Answer (from comments) to push it out of unanswered queue:

If you mean the value of the limit squared, the the latter would be appropriate.