Note that only 5 Fermat primes are known, namely, , , , , and .
A.M.Gleason has proved that if the use of the angle-trisector is allowed, then the constructible polygons have sides of the form , where the 's are distinct Pierpont primes.
The first such that a regular polygon with sides can be constructed with ruler and compass are 3, 4, 5, 6, 8, 10, 12, 15, 16, 17, 20, 24, 30, 32, 34, 40, 48, 51, 60, 64, 68, 80, 85, 96, 102 more terms