OFFSET
1,2
EXAMPLE
a(4)=5 because the numbers 6, 7, 9, 12 and 16 each have 4 quadratic residues.
MATHEMATICA
t=Table[Length[Union[Mod[Range[0, n/2]^2, n]]], {n, 10000}]; Table[Length[Position[t, n]], {n, 100}]
CROSSREFS
KEYWORD
nonn
AUTHOR
T. D. Noe, Aug 25 2005
STATUS
approved