For with odd and , if there exists an integer such that
then is prime. A prime of this form is known as a Proth prime.
For with odd and , if there exists an integer such that
then is prime. A prime of this form is known as a Proth prime.
Weisstein, Eric W. "Proth's Theorem." From MathWorld--A Wolfram Web Resource. https://mathworld.wolfram.com/ProthsTheorem.html