Which Pairs (p,q) Satisfy 2^p+3^q and 2^q+3^p Being Prime?

  • Thread starter Thread starter rrronny
  • Start date Start date
rrronny
Messages
7
Reaction score
0
Let \mathbb{P} the set of primes. Let's 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.
 
Physics news on Phys.org
You have to show your attempts to receive help. This is a forum policy.
 
Borek said:
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).
 
wait... 6 is not a prime...
 
quantumdoodle said:
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.
 
quantumdoodle said:
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).
 
##\textbf{Exercise 10}:## I came across the following solution online: Questions: 1. When the author states in "that ring (not sure if he is referring to ##R## or ##R/\mathfrak{p}##, but I am guessing the later) ##x_n x_{n+1}=0## for all odd $n$ and ##x_{n+1}## is invertible, so that ##x_n=0##" 2. How does ##x_nx_{n+1}=0## implies that ##x_{n+1}## is invertible and ##x_n=0##. I mean if the quotient ring ##R/\mathfrak{p}## is an integral domain, and ##x_{n+1}## is invertible then...
The following are taken from the two sources, 1) from this online page and the book An Introduction to Module Theory by: Ibrahim Assem, Flavio U. Coelho. In the Abelian Categories chapter in the module theory text on page 157, right after presenting IV.2.21 Definition, the authors states "Image and coimage may or may not exist, but if they do, then they are unique up to isomorphism (because so are kernels and cokernels). Also in the reference url page above, the authors present two...
I asked online questions about Proposition 2.1.1: The answer I got is the following: I have some questions about the answer I got. When the person answering says: ##1.## Is the map ##\mathfrak{q}\mapsto \mathfrak{q} A _\mathfrak{p}## from ##A\setminus \mathfrak{p}\to A_\mathfrak{p}##? But I don't understand what the author meant for the rest of the sentence in mathematical notation: ##2.## In the next statement where the author says: How is ##A\to...
Back
Top