Least primitive root

Definition

Suppose $n$ is a natural number such that the multiplicative group modulo $n$ is cyclic (i.e., $n$ is either a prime number, or $4$, or a power of an odd prime, or twice the power of an odd prime). The least primitive root or smallest primitive root modulo $n$ is the smallest natural number $a$ such that $a$ is a primitive root modulo $n$.

Particular cases

Here, we only list $n$ equal to a prime or the square of a prime. For something that is a higher power of an odd prime, the smallest primitive root modulo the square of the prime works.

$n$	Smallest primitive root modulo $n$
2	1
3	2
4	3
5	2
7	3
11	2
13	2
17	3