Pierpont prime

A Pierpont prime is a prime number of the form $p=1+2^{x}3^{y}$ with $-1<y\leq x$ . If $x>0$ and $y=0$ then the resulting prime is a Fermat prime. In the Erdős-Selfridge classification of primes (http://planetmath.org/ErdHosSelfridgeClassificationOfPrimes), the Pierpont primes are class 1-. The first few Pierpont primes are 2, 3, 5, 7, 13, 17, 19, 37, 73, 97, 109, 163, 193, 257, 433, 487, 577, 769, etc., listed in A005109 of Sloane’s OEIS.

In 1988, Gleason showed that an $n$ -sided regular polygon can be constructed with ruler and compass if $n$ is the product of two Pierpont primes.

Title	Pierpont prime
Canonical name	PierpontPrime
Date of creation	2013-03-22 16:52:39
Last modified on	2013-03-22 16:52:39
Owner	PrimeFan (13766)
Last modified by	PrimeFan (13766)
Numerical id	4
Author	PrimeFan (13766)
Entry type	Definition
Classification	msc 11A41