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%I #34 Sep 08 2022 08:44:47
%S 3,5,11,23,47,53,71,101,107,131,167,173,197,251,257,293,311,317,353,
%T 383,431,461,467,563,587,593,683,701,773,797,821,827,863,887,911,953,
%U 977,983,1031,1091,1097,1103,1151,1181,1187,1193,1217,1223,1277,1301,1307,1373
%N Primes p such that 7*p + 2 is also prime.
%C Subsequence of A105772. Except for the first term all others are congruent to 5 (mod 6) because 7*(6n+1)+2 is divisible by 3. - _John Cerkan_, Jul 08 2016
%H John Cerkan, <a href="/A023223/b023223.txt">Table of n, a(n) for n = 1..10000</a>
%e 3 is in the sequence because 7 * 3 + 2 = 23, which is prime.
%e 5 is in the sequence because 7 * 5 + 2 = 37, which is prime.
%e 7 is not in the sequence because 7 * 7 + 2 = 51 = 3 * 17.
%t Select[Prime[Range[250]], PrimeQ[7# + 2] &] (* _Alonso del Arte_, Apr 08 2015 *)
%o (Magma) [n: n in [0..100000] | IsPrime(n) and IsPrime(7*n+2)] // _Vincenzo Librandi_, Nov 19 2010]
%o (PARI) lista(nn) = forprime(p=2, nn, if(isprime(7*p+2), print1(p, ", "))); \\ _Altug Alkan_, Jul 08 2016
%Y Cf. A045392, A105772.
%K nonn
%O 1,1
%A _David W. Wilson_
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