Re: [math-fun] Prime factors of 10^N + 1

On Sep 25, 2017, at 5:30 PM, James Davis <lorentztrans@gmail.com> wrote:

Thanks! That saves me a week.

Then perhaps I can waste you some more time? So square-free, the exceptions pop out! By eyeball it seems like 11^2 is a divisor when n = an odd multiple of 11. And 7^2 divides n=21 and 63, and there's even a 13^2 for n=39 (no doubt all these are related to n=3 being 7 11 13?) What is the smallest n divisible by a cube? By two distinct squares? By any square that's relatively prime to 1001?