$17\mid19^{8n}-1\;\;\forall n\in\mathbb{N}$?

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Show that $17\mid19^{8n}-1\;\;\forall n\in\mathbb{N}$. I thought about using arithmetic of the remains, proving that $1\equiv19^{8n}\pmod{17}$ And I could not do it: (

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Hints:

$$19\equiv2\pmod{17}\;,\;\;2^4\equiv-1\pmod{17}\implies$$

$$19^{8n}-1\equiv\left(2^4\right)^{2n}-1\pmod{17}\equiv\ldots$$