Definition:Deficient Number/Definition 3

Definition

Let $n \in \Z_{\ge 0}$ be a positive integer.

$n$ is deficient if and only if it is greater than its aliquot sum.

Sequence

The sequence of deficient numbers begins:

$2, 3, 4, 5, 7, 8, 9, 10, 11, 13, 14, 15, 16, 17, 19, 21, \ldots$