Iterated self-composition of arbitrary function Does there exist some notation that represents the iterative composition of a single-input, single-output function with itself? As in, say, $f_5(x)=f(f(f(f(f(x)))))$.
In other words, going by the above (incorrect, I'm pretty sure) notation:
$f(x)=x+1$, $f_n(m)=m+n$
I'm looking for the correct way to express the notion of "$f_n(x)$" for any $f$.

I've used $f^n$ when there is no confusion with $f(x)^n$.
I've seen $f^{\circ n}$ to emphasize composition.
