#1**0 **

Disprove: If p is prime, then (2^p)-1 is also prime. Help?

Well that was easy :)

I only need to find one time where 2^p-1 is not prime and then it will be disproven!

I just tried them one at a time and found

2^11 = 2048

factor(3047) = 11*277 I used the web2.0calculator for this :)

so

2^11-1 = 11*277 so it is not prime

Hence

If p is prime, then (2^p)-1 is also prime, has been disproven. :)

Melody
Feb 21, 2017

#2**0 **

I think that should be factor (2047) factor (2047) = 23*89 Which also gives a viable answer to disprove the hypothesis.

ElectricPavlov
Feb 22, 2017