nontotient

An integer $n>0$ is called a nontotient if $N_{\varphi }(n)=0$, where $N_{\varphi }$ is the totient valence function. 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 prime, 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	Noncototient