  The BHK mirror symmetry construction stems from work Berglund and Huebsch,
and applies to certain types of Calabi-Yau varieties that are birational to
finite quotients of Fermat varieties. Their definition involves a matrix $A$
and a certain finite abelian group $G$, and we denote the corresponding
Calabi-Yau variety by $Z_{A,G}$. The transpose matrix $A^T$ and the so-called
dual group $G^T$ give rise to the BHK mirror variety $Z_{A^T,G^T}$. In the case
of dimension 2, the surface $Z_{A,G}$ is a K3 surface of BHK type.
  Let $Z_{A,G}$ be a K3 surface of BHK type, with BHK mirror $Z_{A^T,G^T}$.
Using work of Shioda, Kelly shows that the geometric Picard number of $Z_{A,G}$
may be expressed in terms of a certain subset of the dual group $G^T$. We
simplify this formula significantly to show that this Picard number depends
only upon the degree of the mirror polynomial $F_{A^T}$.
