Minimum coprime number conjecture for odd generalized Petersen graphs with k=3

Let $GP(n,3)$ be the generalized Petersen graph, with $n\geq 7$ odd, and let $\mathfrak{pr}(G)$ denote its minimum coprime number. The $k=3$ minimum-coprime-number conjecture. For every odd $n\geq 7$,

$$\mathfrak{pr}(GP(n,3))=2n+3.$$

The source states that this has been verified for small values of $n$, while a minimum coprime labeling in the general case is not known there.