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 A023266 #20 Sep 08 2022 08:44:47 %S A023266 3,7,31,37,41,71,73,83,107,191,283,307,317,337,373,421,631,743,773, %T A023266 821,857,883,967,1283,1297,1361,1451,1567,1571,1637,1823,1973,2137, %U A023266 2207,2351,2417,2677,2683,2837,3011,3083,3271,3331,3517,3571,3691,3727,3793,3877 %N A023266 Primes that remain prime through 2 iterations of function f(x) = 9x + 4. %C A023266 Primes p such that 9*p+4 and 81*p+40 are also primes. - _Vincenzo Librandi_, Aug 04 2010 %H A023266 Harvey P. Dale, <a href="/A023266/b023266.txt">Table of n, a(n) for n = 1..10000</a> %t A023266 Select[Prime[Range[600]],AllTrue[Rest[NestList[9#+4&,#,2]],PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, Jul 15 2016 *) %o A023266 (Magma) [n: n in [1..100000] | IsPrime(n) and IsPrime(9*n+4) and IsPrime(81*n+40)] // _Vincenzo Librandi_, Aug 04 2010 %K A023266 nonn %O A023266 1,1 %A A023266 _David W. Wilson_