Power of 3
Number Theory
Level
1
\[\begin{array} { r c r } 3^3 &=& {\color{red}{2}}7 \\ 3^4 &=& {\color{red}{8}}1 \\ 3^5 &=& 2{\color{red}{4}}3\\ 3^6 &=& 7{\color{red}{2}}9\\ 3^7 &=& 21{\color{red}{8}}7 \\ 3^8 &=& 65{\color{red}{6}}1 \end{array} \]
The above shows the first few powers of 3, starting from \(3^3\). Is it true that the second last digit (from the right) of \(3^n\) for integers \(n\,(> 2)\) is always an even number?
by
Áron Bán-Szabó