Question

Show that if 2n + 1 is a prime number, then n = 0 or n is a power of 2

Answer 1

2n+1,ifn=0 then 2+1=3it is prime no.
if n is 1 2^1+1=3 it is prime no.
if n is 2 then 2^2+1=5it is also a prime no.