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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 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 STATUS approved

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