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 A023243 #28 Sep 08 2022 08:44:47 %S A023243 7,13,31,37,67,73,79,139,151,181,367,541,613,661,709,739,787,811,829, %T A023243 997,1087,1117,1123,1249,1327,1669,1753,1801,1861,1999,2011,2113,2179, %U A023243 2239,2293,2473,2557,2659,2713,2719,3037,3181,3187,3271,3301,3517,3727,3793 %N A023243 Primes that remain prime through 2 iterations of the function f(x) = 2x + 5. %C A023243 Primes p such that 2*p+5 and 4*p+15 are also primes. - _Vincenzo Librandi_, Aug 04 2010 %H A023243 John Cerkan, <a href="/A023243/b023243.txt">Table of n, a(n) for n = 1..10000</a> %F A023243 a(n) == 1 (mod 6). - _John Cerkan_, Sep 12 2016 %o A023243 (Magma) [n: n in [0..100000] | IsPrime(n) and IsPrime(2*n+5) and IsPrime(4*n+15)] // _Vincenzo Librandi_, Aug 04 2010 %o A023243 (PARI) is(n)=n%6==1 && isprime(2*n+5) && isprime(4*n+15) && isprime(n) \\ _Charles R Greathouse IV_, Sep 12 2016 %Y A023243 Subsequence of A023205 and A089038. %K A023243 nonn,easy %O A023243 1,1 %A A023243 _David W. Wilson_