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%I #11 Sep 08 2022 08:45:41
%S 2,3,19,53,59,239,269,313,379,449,613,823,829,1373,1723,2699,4019,
%T 5209,5233,5923,6079,6389,8069,8663,8849,8933,11239,11369,12269,12503,
%U 13669,13879,14543,15263,15583,15649,16229,16453,16619,17333,18049,18583
%N Primes p such that 6p-7, 6p-5, 6p-1 are all prime.
%H Vincenzo Librandi, <a href="/A157042/b157042.txt">Table of n, a(n) for n = 1..1000</a>
%e For p=2, (5,7,11 prime); p=3, (11,13,17 prime); p=19, (107,109,113);
%p 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
%t Select[Prime@Range@20000, PrimeQ[6 # - 1] && PrimeQ[6 # - 7] && PrimeQ[6 # - 5] &] (* _Vincenzo Librandi_, Sep 11 2013 *)
%t Select[Prime[Range[2200]],AllTrue[6#-{1,5,7},PrimeQ]&] (* _Harvey P. Dale_, Mar 04 2022 *)
%o (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
%Y Cf. A157043.
%K nonn,easy
%O 1,1
%A _Vincenzo Librandi_, Feb 22 2009
%E Corrected (269 added) and extended by _Emeric Deutsch_, Mar 01 2009
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