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 A023258 #23 Sep 08 2022 08:44:47 %S A023258 5,17,29,37,89,127,199,229,269,347,359,379,397,499,769,809,929,947, %T A023258 977,1049,1087,1129,1277,1279,1367,1409,1439,1489,1499,1607,1609,1787, %U A023258 2017,2039,2089,2399,2539,2707,2819,2837,2957,3089,3109,3217,3229,3389,3499 %N A023258 Primes that remain prime through 2 iterations of function f(x) = 6x + 7. %C A023258 Primes p such that 6*p+7 and 36*p+49 are also primes. - _Vincenzo Librandi_, Aug 04 2010 %H A023258 John Cerkan, <a href="/A023258/b023258.txt">Table of n, a(n) for n = 1..10000</a> %F A023258 a(n) = 7 or 9 (mod 10) for n > 1. - _John Cerkan_, Sep 14 2016 %t A023258 nrpQ[n_]:=AllTrue[Rest[NestList[6#+7&,n,2]],PrimeQ]; Select[Prime[ Range[ 500]],nrpQ] (* _Harvey P. Dale_, Oct 12 2020 *) %o A023258 (Magma) [n: n in [1..100000] | IsPrime(n) and IsPrime(6*n+7) and IsPrime(36*n+49)] // _Vincenzo Librandi_, Aug 04 2010 %Y A023258 Subsequence of A023222, A153218. - _John Cerkan_, Sep 14 2016 %K A023258 nonn %O A023258 1,1 %A A023258 _David W. Wilson_