Determine the total number of positive integer values of N < 20150 such that:
2^N - N² is divisible by 17

(In reply to computer solution by Charlie)

It's not surprising that this can be readily solved by computer.  The challenge is to explain the result.

I would have guessed that 1/17 of the numbers would work, but 20149/17 ≈ 1185.235
but double this and you get 2370.47
so why do roughly 2/17 of numbers work?

Something interesting is going on.
I don't have time to investigate right now.

Posted by Jer on 2015-08-12 22:29:12