Definition:Odd Integer/Odd-Times Odd/Sequence

Definition

The sequence of odd-times odd integers begins:

$9, 15, 21, 25, 27, \ldots$

This sequence is A071904 in the On-Line Encyclopedia of Integer Sequences (N. J. A. Sloane (Ed.), 2008).

Euclid's Definition

In the words of Euclid:

An odd-times odd number is that which is measured by an odd number according to an odd number.

(The Elements: Book $\text{VII}$: Definition $10$)