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A028792 Nonsquares mod 79. 1
3, 6, 7, 12, 14, 15, 17, 24, 27, 28, 29, 30, 33, 34, 35, 37, 39, 41, 43, 47, 48, 53, 54, 56, 57, 58, 59, 60, 61, 63, 66, 68, 69, 70, 71, 74, 75, 77, 78 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Table of n, a(n) for n=1..39.

FORMULA

Legendre symbol (a(n)/79) = -1. - Alonso del Arte, Jan 15 2017

EXAMPLE

x^2 = 7 mod 79 has no solutions, hence 7 is in the sequence.

x^2 = 8 mod 79 has the solutions x = 18 and x = 61, so 8 is not in the sequence.

MATHEMATICA

Complement[Range[78], PowerMod[Range[78], 2, 79]] (* Alonso del Arte, Jan 15 2017 *)

PROG

(PARI) isok(n) = (n < 79) && (kronecker(n, 79) == -1); \\ Michel Marcus, Jan 15 2017

(PARI) isok(n) = (n < 79) && (! issquare(Mod(n, 79))); \\ Michel Marcus, Jan 15 2017

(Scala) (0 to 78).diff((1 to 79).map(n => n * n % 79)) // Alonso del Arte, Jan 22 2020

(MAGMA) [n: n in [0..78] | not IsSquare(R! n) where R:= ResidueClassRing(79)]; // Vincenzo Librandi, Jan 23 2020

CROSSREFS

Cf. A010440 (complement), A096013 (row 79).

Sequence in context: A182181 A138038 A095029 * A325804 A144795 A077459

Adjacent sequences:  A028789 A028790 A028791 * A028793 A028794 A028795

KEYWORD

nonn,fini,full,easy

AUTHOR

N. J. A. Sloane

STATUS

approved

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Last modified April 22 22:19 EDT 2021. Contains 343197 sequences. (Running on oeis4.)