Consider the function $f(n, i)$ which returns the exponent of the $p_i$ in the factorisation of $n$, where $p_i$ is the $i$-th prime.
Question: is there a standard label for $f$?
Context: In the first edition of my Gödel book, I (thoughtlessly!) used the notation $\mathit{exp}(n, i)$, with 'exp' for 'exponent'. But of course that notation invites the misreading '$n$ to the power $i$' (taking 'exp' for exponential). Ooops! I'd like to do better in the second edition. Suggestions?