OFFSET
1,3
MATHEMATICA
Union[PowerMod[Range[81], 2, 81]] (* Alonso del Arte, Dec 27 2019 *)
PROG
(Sage) [quadratic_residues(81)] # Zerinvary Lajos, May 28 2009
(Scala) (1 to 81).map(n => (n * n) % 81).toSet.toSeq.sorted // Alonso del Arte, Dec 27 2019
CROSSREFS
KEYWORD
nonn,fini,full,easy
AUTHOR
STATUS
approved