Regular Prime

In number theory, a regular prime is a prime number p > 2 that does not divide the class number of the p-th cyclotomic field.

The first few regular primes are:

3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 41, ... (sequence A007703 in OEIS)
List of unsolved problems in mathematics
Are there infinitely many regular primes, and if so is their relative density ?

Read more about Regular Prime:  Kummer's Criterion, Properties, Irregular Primes, Irregular Pairs, History

Famous quotes containing the words regular and/or prime:

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    “One’s prime is elusive. You little girls, when you grow up, must be on the alert to recognize your prime at whatever time of your life it may occur. You must then live it to the full.”
    —Muriel Spark (b. 1918)