1,3
(Other) sage: [quadratic_residues(21)]# [From Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 24 2009]
Sequence in context: A035510 A187898 A032778 * A010403 A032709 A024797
Adjacent sequences: A010380 A010381 A010382 * A010384 A010385 A010386
nonn,fini,full
N. J. A. Sloane (njas(AT)research.att.com).