Hi there,

I stumbled upon a weird question in one of my exams which I couldn't solve so I out of curiosity I wanted to see what the solution could be. Here goes:

Given some natural number N and some natural number Z, how would you find out if the following summation is divisible by Z:

Any ideas on how to check if the above is divisible by Z without actually having to solve it? Is there some sort of pattern?

Regards,

Austin