Question 115
Prove that the number
$$
\overbrace{222\ldots2}^{n \text{ digits}} - 3^n + 1
$$
is divisible by $7$ for any positive integer $n$. (Matko Ljulj)
$$
\overbrace{222\ldots2}^{n \text{ digits}} - 3^n + 1
$$
is divisible by $7$ for any positive integer $n$. (Matko Ljulj)