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A157042 Primes p such that 6p-7, 6p-5, 6p-1 are all prime. 2
2, 3, 19, 53, 59, 239, 269, 313, 379, 449, 613, 823, 829, 1373, 1723, 2699, 4019, 5209, 5233, 5923, 6079, 6389, 8069, 8663, 8849, 8933, 11239, 11369, 12269, 12503, 13669, 13879, 14543, 15263, 15583, 15649, 16229, 16453, 16619, 17333, 18049, 18583 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

EXAMPLE

For p=2, (5,7,11 prime); p=3, (11,13,17 prime); p=19, (107,109,113);

MAPLE

a := proc (n) if isprime(6*ithprime(n)-7) = true and isprime(6*ithprime(n)-5) = true and isprime(6*ithprime(n)-1) = true then ithprime(n) else end if end proc: seq(a(n), n = 1 .. 2200); # Emeric Deutsch, Mar 01 2009

MATHEMATICA

Select[Prime@Range@20000, PrimeQ[6 # - 1] && PrimeQ[6 # - 7] && PrimeQ[6 # - 5] &] (* Vincenzo Librandi, Sep 11 2013 *)

PROG

(MAGMA) [p: p in PrimesUpTo(20000) | IsPrime(6*p-7) and IsPrime(6*p-5) and IsPrime(6*p-1)]; // Vincenzo Librandi, Sep 11 2013

CROSSREFS

Cf. A157043.

Sequence in context: A289860 A248702 A171149 * A128968 A153409 A143893

Adjacent sequences:  A157039 A157040 A157041 * A157043 A157044 A157045

KEYWORD

nonn,easy

AUTHOR

Vincenzo Librandi, Feb 22 2009

EXTENSIONS

Corrected (269 added) and extended by Emeric Deutsch, Mar 01 2009

STATUS

approved

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Last modified March 29 14:37 EDT 2020. Contains 333107 sequences. (Running on oeis4.)