Looking for Fibonacci Base-2 Pseudoprimes

Abstract

In this paper, we examine computationally the results of combining two well-known, simple, and imperfect tests for primality: the Fermat base-2 test, and the Fibonacci test. Although considerable attention has been paid to various properties of composite integers which pass the base-2 test (base-2 pseudoprimes), no comparable study of Fibonacci and base-2 Fibonacci tests exists in the literature. Our study tabulates various empirical properties of these numbers. Among other things, we conclude that there are no base-2 Fibonacci pseudoprimes less than $10^{15}$ which are congruent to 2 or 3 (modulo 5).