legendreSymbol -- Compute the Legendresymbol.

• Usage:

  legendreSymbol(a,p)

• Inputs:
  • a, an integer,
  • p, an integer, an odd prime.
• Outputs:
  • an integer, 0 if a is divisible by p, 1 if a is a quadratic residue mod p and -1 if a is not a quadratic residue mod p.

i1 : legendreSymbol(4,7)

o1 = 1

i2 : legendreSymbol(5,7)

o2 = -1

i3 : legendreSymbol(14,7)

o3 = 0