Ta có : \(2^{16}=\left(2^4\right)^4=16^4\)
Ta có : \(16\equiv\left(-1\right)\left(mod17\right)\)
\(\Leftrightarrow16^4\equiv1\left(mod17\right)\)
\(\Leftrightarrow16^4:17\) dư 1
Hay : \(2^{16}\) cha 17 dư 1.
Ta có: \(2^4\equiv-1\left(mod17\right)\)
\(\Rightarrow\left(2^4\right)^4\equiv\left(-1\right)^4\left(mod17\right)\)
\(\Rightarrow2^{16}\equiv1\left(mod17\right)\)
Vậy \(2^{16}\) chia 17 dư 1