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 A023241 #38 Feb 16 2025 08:32:34 %S A023241 5,7,11,17,31,41,47,61,67,97,101,151,167,227,251,257,271,347,367,557, %T A023241 587,601,607,641,647,727,941,971,1091,1097,1117,1181,1217,1277,1291, %U A023241 1361,1427,1447,1481,1487,1601,1607,1657,1741,1747,1777,1861,1867,1901,1987 %N A023241 Primes that remain prime through 2 iterations of function f(x) = x + 6. %C A023241 Primes p such that p+6 and p+12 are also primes. %H A023241 Lei Zhou, <a href="/A023241/b023241.txt">Table of n, a(n) for n = 1..10000</a> %H A023241 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/PrimeTriplet.html">Prime Triplet</a> %t A023241 triq[p_] := And[PrimeQ[p + 6], PrimeQ[p + 12]]; Select[Prime[Range[1000]], triq] (* _Ben Branman_, Sep 03 2012 *) %t A023241 nrpQ[n_]:=AllTrue[Rest[NestList[#+6&,n,2]],PrimeQ]; Select[Prime[Range[ 300]],nrpQ] (* Requires Mathematica version 10 or later *) (* _Harvey P. Dale_, Jan 27 2021 *) %o A023241 (Magma) [n: n in [0..1000] | IsPrime(n) and IsPrime(n+6) and IsPrime(n+12)] // _Vincenzo Librandi_, Nov 20 2010 %K A023241 nonn %O A023241 1,1 %A A023241 _David W. Wilson_