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 A024903 Numbers n such that 7*n-4 is prime. 7
 1, 3, 5, 9, 11, 15, 23, 29, 33, 35, 39, 41, 45, 51, 53, 59, 69, 75, 81, 83, 89, 93, 95, 111, 113, 119, 123, 135, 141, 143, 149, 159, 161, 165, 171, 179, 183, 185, 189, 195, 209, 213, 221, 225, 231, 233, 239, 243, 251, 261, 269, 273, 279, 299, 305, 321, 335, 341 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,2 LINKS Vincenzo Librandi, Table of n, a(n) for n = 1..1000 FORMULA a(n) = A033868(n-1)-1 = A089033(n-1)+1 = A090614(n-1)*2+1. MATHEMATICA Select[Range[350], PrimeQ[7 # - 4] &] (* Vincenzo Librandi, Sep 26 2012 *) PROG (MAGMA) [n: n in [1..400] | IsPrime(7*n-4)]; // Vincenzo Librandi, Nov 20 2010 (PARI) is(n)=isprime(7*n-4) \\ Charles R Greathouse IV, Feb 17 2017 CROSSREFS Cf. A045437 (associated primes), A090613 (gives prime index). Cf. A033868, A089033, A090614. Sequence in context: A169780 A233760 A244780 * A322957 A018486 A261194 Adjacent sequences:  A024900 A024901 A024902 * A024904 A024905 A024906 KEYWORD nonn,easy AUTHOR STATUS approved

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Last modified May 13 16:56 EDT 2021. Contains 343862 sequences. (Running on oeis4.)