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IsProbPrime --
checks if an integer is a probable prime
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IsProbPrime(N: INT): BOOL |
This function returns
true if its integer argument passes a fairly
stringent primality test; otherwise it returns
false. There is a very
small chance of the function returning
true even when the argument is
composite; however, if it returns
false, we are certain that the
argument is composite. Some people call it a "compositeness test".
This function cannot be interrupted, so be wary of inputs larger than
about
2^100000 (which already takes a few minutes).
/**/ IsProbPrime(2);
true
/**/ IsProbPrime(1111111111111111111);
true
/**/ [N in 1..1111 | IsProbPrime((10^N-1)/9)]; -- only five values are known
[2, 19, 23, 317, 1031] -- next might be 49081
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