For an Odd Prime and a Positive Integer which is not a multiple of ,
See also Quadratic Residue
References
Rosen, K. H. Ch. 9 in Elementary Number Theory and Its Applications, 3rd ed. Reading, MA: Addison-Wesley, 1993.
Shanks, D. Solved and Unsolved Problems in Number Theory, 4th ed. New York: Chelsea, pp. 33-37, 1993.
Wagon, S. Mathematica in Action. New York: W. H. Freeman, p. 293, 1991.