A -rough number is an integer having only prime factors greater than or equal to . A number that is -rough is thus not a -smooth number. However, a prime is both -smooth and -rough because neither inequality is strict.
For example, 771166905830363 is 7-rough since, in addition to having 7 as a prime factor, it has greater primes as factors. By comparison, 93386641873154605056 is not 7-rough, and is in fact 7-smooth, since all its divisors are 2, 3, and powers of those small primes.
|Date of creation||2013-03-22 18:09:46|
|Last modified on||2013-03-22 18:09:46|
|Last modified by||PrimeFan (13766)|