An integer n>0 is called a nontotientMathworldPlanetmath if Nϕ(n)=0, where Nϕ is the totient valence functionMathworldPlanetmath. This is the case of any odd integer greater than 1. This is also the case of twice a prime that isn’t a Sophie Germain primeMathworldPlanetmath, one more than a prime, an oblong number that is the product of a prime and one more or less than that prime, etc.

Sloane’s OEIS lists even values in A005277 and all values together in A007617.

Title nontotient
Canonical name Nontotient
Date of creation 2013-03-22 15:51:20
Last modified on 2013-03-22 15:51:20
Owner PrimeFan (13766)
Last modified by PrimeFan (13766)
Numerical id 6
Author PrimeFan (13766)
Entry type Definition
Classification msc 11A25
Related topic NoncototientMathworldPlanetmath