Canad. J. Math. 62(2010), 582-594
Printed: Jun 2010
Sergei V. Konyagin
Igor E. Shparlinski
An x-pseudopower to base g is a positive integer that is not a power of g, yet is so modulo p for all primes $ple x$. We improve an upper bound for the least such number, due to E.~Bach, R.~Lukes, J.~Shallit, and H.~C.~Williams. The method is based on a combination of some bounds of exponential sums with new results about the average behaviour of the multiplicative order of g modulo prime numbers.
11A07 - Congruences; primitive roots; residue systems
11L07 - Estimates on exponential sums
11N36 - Applications of sieve methods