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A028733 Nonsquares mod 20. 1
2, 3, 6, 7, 8, 10, 11, 12, 13, 14, 15, 17, 18, 19 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..14.

MATHEMATICA

Complement[Range[0, 19], PowerMod[Range[20], 2, 20]] (* Alonso del Arte, Dec 20 2019 *)

PROG

(Scala) (0 to 19).diff((1 to 20).map(n => (n * n) % 20)) // Alonso del Arte, Dec 20 2019

CROSSREFS

Cf. A010382.

Sequence in context: A059590 A276156 A144705 * A028789 A038100 A299407

Adjacent sequences:  A028730 A028731 A028732 * A028734 A028735 A028736

KEYWORD

nonn,fini,full,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified August 4 16:34 EDT 2020. Contains 336202 sequences. (Running on oeis4.)