I need to use a lemma in a paper. Here it is:
Lemma: Any $m \geq 52$ can be written in the form $m=\binom{n+1}{2}+a-3b-6d$ for $n \geq 13$, $a,b \in \{0,1\}$, and $d \in \{0,1,\ldots,2 \lfloor n/2 \rfloor-6\}$.
While I've written a proof, I don't have room in the paper to include the proof due to page limits. Also, the proof is not relevant to the rest of the paper.
Question: Is it acceptable use of math.SE to ask a question What is a proof of Lemma X? and answer it myself, with the intention of citing it in my paper?
It seems better to write "a proof can be found at [math.SE link]" than "we omit a proof" in the paper.