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 A023240 #35 Sep 08 2022 08:44:47 %S A023240 2,5,7,13,17,19,23,37,41,43,47,59,61,71,73,83,101,103,127,131,139,149, %T A023240 157,197,199,223,233,239,257,269,271,281,293,307,311,331,349,353,373, %U A023240 401,409,421,433,463,467,479,491,499,503,509,541,547,563,577,587,593,607,619 %N A023240 Primes p such that 10*p + 9 is also prime. %H A023240 John Cerkan, <a href="/A023240/b023240.txt">Table of n, a(n) for n = 1..10000</a> %t A023240 Select[Prime@ Range@ 120, PrimeQ[10 # + 9] &] (* _Michael De Vlieger_, Sep 12 2016 *) %o A023240 (Magma) [ n: n in PrimesUpTo(700) | IsPrime(10*n+9) ]; // _Vincenzo Librandi_, Nov 20 2010 %Y A023240 Subsequence of A102700. %K A023240 nonn %O A023240 1,1 %A A023240 _David W. Wilson_