Let $A\in \mathbb{Z}^{n\times n}$ with $\det A\neq 0$. I was wondering whether $A^{-1}$ must have an entry of the form $p/q$ with $q=\det A$ and $(p,q)=1$ (that is, an irreducible fraction).
By the adjugate form of the inverse, this is equivalent to some minor of $A$ being coprime with $\det A$.
Playing around with $2\times 2$ matrices, it seems to hold for $n=2$, and I tried using Laplace's expansion to generalize to higher dimensions, but got nowhere. Does it hold in general?