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 A023239 #31 Sep 08 2022 08:44:47 %S A023239 3,13,19,31,61,67,79,97,109,127,163,199,223,229,241,277,283,313,367, %T A023239 379,421,433,439,463,487,523,541,547,571,619,631,673,691,751,757,787, %U A023239 811,823,829,853,859,883,937,967,1033,1093,1117,1171,1237,1249,1291,1303,1321 %N A023239 Primes p such that 10*p + 7 is also prime. %H A023239 John Cerkan, <a href="/A023239/b023239.txt">Table of n, a(n) for n = 1..10000</a> %F A023239 a(n) == 1 (mod 6), for n > 1. - _John Cerkan_, Sep 12 2016 %t A023239 Select[Prime[Range[200]], PrimeQ[10# + 7] &] (* _Alonso del Arte_, Jun 24 2014 *) %o A023239 (Magma) [n: n in [0..1000] | IsPrime(n) and IsPrime(10*n+7)] // _Vincenzo Librandi_, Nov 20 2010 %Y A023239 Cf. A023238. %Y A023239 Subsequence of A102342. %K A023239 nonn %O A023239 1,1 %A A023239 _David W. Wilson_