View Full Version : On the primality of 2^p+3^q
rrronny
Sep15-09, 10:33 AM
Let \mathbb{P} the set of primes. Lets p,q \in \mathbb{P} and p \le q. Find the pairs (p,q) such that 2^p+3^q and 2^q+3^p are simultaneously primes.
You have to show your attempts to receive help. This is a forum policy.
rrronny
Sep15-09, 11:16 AM
You have to show your attempts to receive help. This is a forum policy.
Hi Borek,
I do not have a solution for this problem...
I found only four solutions: (1,1), (1,2), (2,3), (2,6).
quantumdoodle
Sep19-09, 11:38 AM
wait... 6 is not a prime...
ramsey2879
Sep19-09, 01:27 PM
wait... 6 is not a prime...
Neither is 1 so only one of the 4 pairs posted is acceptable. There is still another very obvious pair that was overlooked.
rrronny
Sep19-09, 01:35 PM
wait... 6 is not a prime...
Sorry... :blushing: I meant the sixth prime number.
In summary, then, the only solutions (p,q) that I found are (2,2),(2,3),(3,5), (3,13).
vBulletin® v3.7.6, Copyright ©2000-2009, Jelsoft Enterprises Ltd.