Prime numbers from infinite prime number proof

Click For Summary
SUMMARY

The discussion centers on the exploration of prime numbers derived from the product of all primes, specifically through the formulas \(\pm1+\prod_{p\in P} p\) for a finite set of primes \(P\). The products of the first \(n\) primes are identified as primorials, while adding or subtracting one from these yields the Euclid numbers and Kummer numbers, respectively. The prime Euclid numbers do not have a widely recognized name, although they could be referred to as "Euclid primes." The question of whether there are infinitely many prime Euclid numbers remains unsolved.

PREREQUISITES
  • Understanding of prime numbers and their properties
  • Familiarity with the concept of primorials
  • Knowledge of Euclid numbers and Kummer numbers
  • Basic grasp of mathematical notation and proofs
NEXT STEPS
  • Research the properties of Euclid numbers and their significance in number theory
  • Explore the concept of Kummer numbers and their relationship to primes
  • Investigate the unsolved question regarding the infinitude of prime Euclid numbers
  • Learn about the Online Encyclopedia of Integer Sequences (OEIS) and its resources on prime sequences
USEFUL FOR

Mathematicians, number theorists, and students interested in prime number theory and the properties of special prime sequences.

jfizzix
Science Advisor
Homework Helper
Insights Author
Messages
757
Reaction score
356
I imagine most everyone here's familiar with the proof that there's an infinite number of primes:

If there were a largest prime
you could take the product of all prime factors
add (or take away) 1 and get another large prime (a contradiction)

So what if you search for larger primes this way?

(2,3,5,7,11,13)

(2*3) +-1 = 6 +-1 = {5,7}
(2*3*5) +-1 = 30+-1 = {29.31}
(2*3*5*7)+-1 = 210+-1 = {209,211} (209 is not prime)
(2*3*5*7*11)+-1 = 2310+-1 = {2309,2311}
(2*3*5*7*11*13)+-1 = 30030+-1={30029,30031} (30031 is not prime)

I have two questions:
Do prime numbers of this sort have a special name? (like Marsenne primes are (powers of 2) +-1?)
Are there infinitely many of them?

This was just an odd thought I had. You can keep going and find products where neither one above or one below is a prime.
 
Mathematics news on Phys.org
I don't know a name of primes of the form \pm1+\prod_{p\in P} p for P a finite set of primes.

One comment, though. I'm not sure whether primality/non-primality of numbers of the above form is that interesting ("interesting" being too subjective for my comment to make any sense :P). The argument to which you're referring generates primes like that based on a hypothesis we know to be false: namely, that P can be chosen to be the finite set of all primes.
 
The products of the first n primes are called the primorials.

If you add 1 to these, you get the Euclid numbers.

If you subtract 1 instead, you get the Kummer numbers.

The prime Euclid numbers (or prime Kummer numbers) don't have special names. They are just the "prime Euclid numbers." I guess you could call them "Euclid primes" (or "Kummer primes") if you wanted to be fancy, but this is not widely-used terminology. You can find a list of the first few prime Euclid numbers on OEIS. I believe the question of whether this list goes on forever is unsolved.

As far as I know, the combined list of prime Euclid numbers and prime Kummer numbers has no name (and isn't even on OEIS as far as I can tell).
 
  • Like
Likes 1 person
Thanks for the info:)
 

Similar threads

  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 3 ·
Replies
3
Views
1K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 24 ·
Replies
24
Views
3K
  • · Replies 3 ·
Replies
3
Views
985
  • · Replies 4 ·
Replies
4
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 8 ·
Replies
8
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K
  • · Replies 1 ·
Replies
1
Views
2K