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A010383 Squares mod 21. 1
0, 1, 4, 7, 9, 15, 16, 18 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..8.

MATHEMATICA

Union[PowerMod[Range[21], 2, 21]] (* Alonso del Arte, Dec 21 2019 *)

PROG

(Sage) [quadratic_residues(21)] # Zerinvary Lajos, May 24 2009

(Scala) (1 to 21).map(n => (n * n) % 21).toSet.toSeq.sorted // Alonso del Arte, Dec 21 2019

CROSSREFS

Row 21 of A096008.

Cf. A028734.

Sequence in context: A032778 A282058 A210497 * A010403 A032709 A243172

Adjacent sequences:  A010380 A010381 A010382 * A010384 A010385 A010386

KEYWORD

nonn,fini,full,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified March 7 09:46 EST 2021. Contains 341869 sequences. (Running on oeis4.)