Adjacent Primes

Date: 11/26/2001 at 18:22:10
From: Will 
Subject: Adjacent Primes

What are adjacent primes?

Thanks a bunch,
Will Little

Date: 11/27/2001 at 17:34:46
From: Doctor Achilles
Subject: Re: Adjacent Primes

Hi Will,

Thanks for writing to Dr. Math.

Adjacent primes are two consecutive odd integers, both of which are 
prime. For example, 3 and 5 are adjacent primes, as are 5 and 7. So 
are 11 and 13 and 17 and 19.

Of course, since prime numbers become more and more scarce are you get 
into larger integers, adjacent primes get few and far between.  I once 
heard a conjecture that there are an infinite number of adjacent 
primes, but I don't know whether it's ever been proven or not.

Hope this helps.  Let me know if I can be of more assistance.

- Doctor Achilles, The Math Forum
  http://mathforum.org/dr.math/