Question 4
Let $a_1,\ldots,a_{1000}$ be integers and write their squares around a circle. The sum of any 41 consecutive numbers on this circle is divisible by $41^2$. Must each $a_i$ be divisible by 41?
ITOT · ITOT 41 Autumn 2019 - Junior O - Practice (sum 22; official best three 14)