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A028753 Nonsquares mod 40. 1
2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15, 17, 18, 19, 21, 22, 23, 26, 27, 28, 29, 30, 31, 32, 33, 34, 35, 37, 38, 39 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..31.

MATHEMATICA

Complement[Range[0, 39], PowerMod[Range[40], 2, 40]] (* Alonso del Arte, Feb 20 2020 *)

PROG

(Scala) (0 to 39).diff((1 to 40).map(n => n * n % 40)) // Alonso del Arte, Feb 20 2020

(MAGMA) [n: n in [0..39] | not IsSquare(R! n) where R:= ResidueClassRing(40)]; // Vincenzo Librandi, Feb 21 2020

CROSSREFS

Cf. A010401.

Sequence in context: A028813 A158276 A028793 * A336918 A028745 A028777

Adjacent sequences:  A028750 A028751 A028752 * A028754 A028755 A028756

KEYWORD

nonn,fini,full,easy

AUTHOR

N. J. A. Sloane.

STATUS

approved

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Last modified April 10 22:23 EDT 2021. Contains 342856 sequences. (Running on oeis4.)