p−1 divides n−1 for prime divisors p of n and n has this property, by Korselt's criterion.
Sarkozy's theorem guarantees that for sufficiently large n, a certain function of n does not have this property. An integer n divides an −a i  p−1 divides n−1 for prime divisors p of n and n has this property, by Korselt's criterion. A word has this property if none of its subwords consist of two duplicated subwords. The Möbius function of all numbers without this property is zero. A conjecture of Erdos states that for all n > 4, 2n choose n has this property. An expression is in simplest radical form if the number under the square root has this property. For ten points, identify this property held by numbers with no duplicated prime factors, that is, no factors which are perfect squares.
Sarkozy's theorem guarantees that for sufficiently large n, a certain function of n does not have this property.
squarefree