On the number of nonquadratic residues which are not primitive roots
Volume 100 / 2004
Colloquium Mathematicum 100 (2004), 91-93
MSC: Primary 11A25.
DOI: 10.4064/cm100-1-8
Abstract
We show that there exist infinitely many positive integers $r$ not of the form $(p-1)/2-\phi (p-1)$, thus providing an affirmative answer to a question of Neville Robbins.
