This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A023223 #41 Aug 20 2024 15:26:49 %S A023223 3,5,11,23,47,53,71,101,107,131,167,173,197,251,257,293,311,317,353, %T A023223 383,431,461,467,563,587,593,683,701,773,797,821,827,863,887,911,953, %U A023223 977,983,1031,1091,1097,1103,1151,1181,1187,1193,1217,1223,1277,1301,1307,1373 %N A023223 Primes p such that 7*p + 2 is also prime. %C A023223 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 A023223 John Cerkan, <a href="/A023223/b023223.txt">Table of n, a(n) for n = 1..10000</a> %e A023223 3 is in the sequence because 7 * 3 + 2 = 23, which is prime. %e A023223 5 is in the sequence because 7 * 5 + 2 = 37, which is prime. %e A023223 7 is not in the sequence because 7 * 7 + 2 = 51 = 3 * 17. %t A023223 Select[Prime[Range[250]], PrimeQ[7# + 2] &] (* _Alonso del Arte_, Apr 08 2015 *) %o A023223 (Magma) [n: n in [0..100000] | IsPrime(n) and IsPrime(7*n+2)]; // _Vincenzo Librandi_, Nov 19 2010 %o A023223 (PARI) lista(nn) = forprime(p=2, nn, if(isprime(7*p+2), print1(p, ", "))); \\ _Altug Alkan_, Jul 08 2016 %Y A023223 Cf. A045392, A105772. %K A023223 nonn %O A023223 1,1 %A A023223 _David W. Wilson_