Definition:Nontotient

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Definition

A nontotient is a positive even integer $n$ such that:

$\nexists m \in \Z_{>0}: \phi \left({m}\right) = n$

where $\phi \left({m}\right)$ denotes the Euler $\phi$ function.


That is, a nontotient is a positive even integer which is not the totient of any positive integer.


Sequence

The sequence of nontotients begins:

$14, 26, 34, 38, 50, 62, 68, 74, 76, 86, 90, 94, 98, 114, 118, 122, 124, 134, 142, 146, 152, 154, \ldots$


Also see


Sources