Question Number 187007 by Humble last updated on 12/Feb/23
$${prove}\:\:{that} \\ $$$$\mathrm{7}^{{k}+\mathrm{1}} \mid\:\mathrm{13}^{\mathrm{7}{k}} \:+\:\mathrm{1}\:,\:\forall{k}\in\mathbb{N} \\ $$$$ \\ $$$$ \\ $$$$ \\ $$
Commented by Frix last updated on 13/Feb/23
$$\mathrm{It}'\mathrm{s}\:\mathrm{wrong}\:\mathrm{for}\:{k}=\mathrm{2} \\ $$
Commented by Humble last updated on 14/Feb/23
$${may}\:{i}\:\:{see}\:\:{your}\:{approach}? \\ $$