# Primes of the form 2^m + 1

1. Oct 12, 2004

### Zurtex

I've been asked to research primes of the form 2^m + 1, I've found all the known primes but now I've been asked to find out why m must be of the form 2^x for some natrual number x for 2^m + 1 to be prime. I've found quite a lot on this but nothing that clearly proves it, can anyone give me a good link or something please.

2. Oct 12, 2004

### Zurtex

Never mind, worked it out myself