What is the automorphism group of direct sum of dihedral group of order $8$, $D_4$?
For example, $\mathrm{Aut}(D_4)$ is isomorphic to $D_4$. How about $\mathrm{Aut}(D_4\times D_4)$, $\mathrm{Aut}(D_4\times D_4\times D_4)$, and $\mathrm{Aut}(D_4\times D_4 \times D_4 \times D_4)$?