1Department of Mathematics East Tennessee State University Johnson City, TN 37614-0002 USA
2Department of Mathematics University of Johannesburg Auckland Park, South Africa
3Department of Mathematics Wingate University Wingate, North Carolina 28174 USA
4Professor Emeritus School of Computing Clemson University Clemson, SC 29634 USA
5Department of Computer Science Appalachain State University Boone, NC 28608 USA