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 A023238 #32 Sep 08 2022 08:44:47 %S A023238 2,5,7,11,17,19,23,29,31,37,43,59,61,67,73,101,103,109,137,149,173, %T A023238 191,193,197,199,211,227,229,233,239,263,269,271,283,331,337,353,359, %U A023238 367,373,379,383,401,409,449,467,479,499,523,541,557,569,607,613,617,647,673,683 %N A023238 Primes p such that 10*p + 3 is also prime. %H A023238 John Cerkan, <a href="/A023238/b023238.txt">Table of n, a(n) for n = 1..10000</a> %p A023238 A023238:=n->`if`(isprime(n) and isprime(10*n+3), n, NULL): seq(A023238(n), n=1..10^3); # _Wesley Ivan Hurt_, Sep 08 2016 %t A023238 Select[Prime[Range[200]], PrimeQ[10# + 3] &] (* _Alonso del Arte_, Jun 24 2014 *) %o A023238 (Magma) [n: n in [0..1000] | IsPrime(n) and IsPrime(10*n+3)] // _Vincenzo Librandi_, Nov 20 2010 %Y A023238 Cf. A023239. %Y A023238 Subsequence of A102338. %K A023238 nonn %O A023238 1,1 %A A023238 _David W. Wilson_