This function calculates efficiently an integer power modulo a given
modulus. Thus
PowerMod(A, B, M)
is equal to
Mod(A^B, M)
, but the former
is computed faster. B must be non-negative.
Example
/**/ PowerMod(12345,41041,41041); -- 41041 is a Carmichael number
12345
/**/ PowerMod(123456789,987654321,32003); -- cannot compute 123456789^987654321 directly
2332