Proth's Theorem
For N=k·2^n+1 with k odd and 2^n>k, if there exists an integer a such that
| a^((N-1)/2)=-1 (mod N), |
then N is prime. A prime of this form is known as a Proth prime.
See also
Proth PrimeExplore with Wolfram|Alpha
WolframAlpha
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Cite this as:
Weisstein, Eric W. "Proth's Theorem." From MathWorld--A Wolfram Resource. https://mathworld.wolfram.com/ProthsTheorem.html