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