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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

Clark Kimberling

STATUS

approved

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Last modified June 1 04:57 EDT 2020. Contains 334758 sequences. (Running on oeis4.)