OFFSET
1,1
EXAMPLE
Quadratic residue of modulus=17=p(4): {1,4,9,16,8,2,15,13,13,15,2,8,16,9,4,1,0} includes p(3)=13, the previous prime, so 17 is entered; Q.residue-set of 11,{1,4,9,5,3,3,5,9,4,1,0} does not include 7, thus 7 is not here.
MATHEMATICA
t=Table[Count[Union[Table[Mod[w^2, Prime[k]], {w, 1, Prime[k]}]], Prime[k-1]], {k, 1, 180}]; Prime[Flatten[Position[t, 1]]]
CROSSREFS
KEYWORD
nonn
AUTHOR
Labos Elemer, Nov 15 2001
STATUS
approved