A028792 Nonsquares mod 79.

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

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 A364292

Adjacent sequences: A028789 A028790 A028791 * A028793 A028794 A028795

Keyword

nonn,fini,full,easy

Author

N. J. A. Sloane

Status

approved