Primitive Divisors of Lucas and Lehmer Sequences

Abstract

Stewart reduced the problem of determining all Lucas and Lehmer sequences whose nth element does not have a primitive divisor to solving certain Thue equations. Using the method of Tzanakis and de Weger for solving Thue equations, we determine such sequences for n ≤ 30. Further computations lead us to conjecture that, for n > 30, the nth element of such sequences always has a primitive divisor