Definition:Odd Integer/Odd-Times Odd

Definition
Let $n \in \Z$, i.e. let $n$ be an integer.

Then $n$ is odd-times odd if it is an odd number greater than $1$ which is not prime.

More precisely, $n$ is odd-times odd if there exist odd numbers $x, y > 1$, such that $n = x y$.

The first few odd-times odd numbers are:
 * $9, 15, 21, 25, 27, \ldots$

Also see

 * Definition:Odd Integer
 * Definition:Even-Times Odd Integer