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 A023261 #22 Sep 08 2022 08:44:47 %S A023261 5,13,31,61,101,103,163,191,233,241,251,433,461,643,751,761,821,863, %T A023261 983,1021,1153,1193,1283,1291,1531,1543,1861,2281,2543,2903,2953,3271, %U A023261 3373,3673,3701,3733,3793,3923,4003,4241,4283,4751,5333,5581,5711,5801,5813 %N A023261 Primes that remain prime through 2 iterations of function f(x) = 8x + 3. %C A023261 Primes p such that 8*p+3 and 64*p+27 are also primes. - _Vincenzo Librandi_, Aug 04 2010 %H A023261 John Cerkan, <a href="/A023261/b023261.txt">Table of n, a(n) for n = 1..10000</a> %F A023261 a(n) = 1 or 3 (mod 10) for n > 1. - _John Cerkan_, Sep 14 2016 %t A023261 Select[Prime[Range[800]],AllTrue[Rest[NestList[8#+3&,#,2]],PrimeQ]&] (* The program uses the AllTrue function from Mathematica version 10 *) (* _Harvey P. Dale_, Aug 12 2017 *) %o A023261 (Magma) [n: n in [1..100000] | IsPrime(n) and IsPrime(8*n+3) and IsPrime(64*n+27)] // _Vincenzo Librandi_, Aug 04 2010 %Y A023261 Subsequence of A005124, A023229. - _John Cerkan_, Sep 14 2016 %K A023261 nonn %O A023261 1,1 %A A023261 _David W. Wilson_