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 A045331 Primes congruent to {1, 2, 3} mod 6; or, -3 is a square mod p. 13
 2, 3, 7, 13, 19, 31, 37, 43, 61, 67, 73, 79, 97, 103, 109, 127, 139, 151, 157, 163, 181, 193, 199, 211, 223, 229, 241, 271, 277, 283, 307, 313, 331, 337, 349, 367, 373, 379, 397, 409, 421, 433, 439, 457, 463, 487, 499, 523, 541, 547, 571, 577, 601, 607, 613 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS -3 is a quadratic residue mod a prime p iff p is in this sequence. LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..1000 MATHEMATICA Select[Prime[Range[200]], MemberQ[{1, 2, 3}, Mod[#, 6]]&]  (* Harvey P. Dale, Mar 31 2011 *) Join[{2, 3}, Select[Range[7, 10^3, 6], PrimeQ]] (* Zak Seidov, May 20 2011 *) PROG (PARI) select(primes(100), n->n%6<5) \\ old versions select(n->n%6<5, primes(100)) \\ new versions \\ Charles R Greathouse IV, May 20, 2011 (MAGMA) [p: p in PrimesUpTo(700) | p mod 6 in [1, 2, 3]]; // Vincenzo Librandi, Aug 08 2012 (Haskell) a045331 n = a045331_list !! (n-1) a045331_list = filter ((< 4) . (`mod` 6)) a000040_list -- Reinhard Zumkeller, Jan 15 2013 CROSSREFS Apart from initial term, same as A007645; apart from initial two terms, same as A002476. Cf. A002313, A033203, A038873, A038874, A057128. Subsequence of A047246. Sequence in context: A051484 A101415 A210393 * A053613 A013645 A130272 Adjacent sequences:  A045328 A045329 A045330 * A045332 A045333 A045334 KEYWORD nonn,nice,easy AUTHOR EXTENSIONS More terms from Henry Bottomley, Aug 10 2000 STATUS approved

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Last modified December 12 17:59 EST 2019. Contains 329960 sequences. (Running on oeis4.)