This app allows you to compute the primality of a Proth number (A number of the form N=k*2^n+1).
Where k is an odd positive integer and 2^n>N.

This app has been tested with numbers in excess of 10,000 digits!

For example 3*2^2+1 is prime because 3*2^2+1 = 13
5^(13-1)/2 +1 mod 5 = 0, so 13 is prime.

For more information view, https://en.m.wikipedia.org/wiki/Proth%27s_theorem