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 A215918 #13 Sep 08 2022 08:46:03 %S A215918 1,2,6,11,16,17,32,37,46,51,76,102,137,142,146,181,216,237,241,247, %T A215918 277,282,297,311,312,332,347,356,396,447,451,466,527,542,576,577,641, %U A215918 692,752,797,871,902,906,941,942,956,1091,1137,1201,1292,1312,1381,1437 %N A215918 Numbers n such that 6*n + {1, 5, 7} are all primes. %C A215918 Subsequence of A056956. %H A215918 Vincenzo Librandi, <a href="/A215918/b215918.txt">Table of n, a(n) for n = 1..1000</a> %F A215918 a(n) = (A022005(n)-1)/6. %t A215918 Select[Range[1437], Union[PrimeQ[6 # + {1, 5, 7}]] == {True} &] (* _T. D. Noe_, Aug 27 2012 *) %o A215918 (PARI) for(n=1,2000,if(isprime(6*n+1)&&isprime(6*n+5)&&isprime(6*n+7),print(n","))) %o A215918 (Magma) [n: n in [1..1000] | forall{6*n+r: r in [1,5,7] | IsPrime(6*n+r)}]; // _Bruno Berselli_, Aug 27 2012 %Y A215918 Cf. A022005, A056956. %K A215918 nonn,easy %O A215918 1,2 %A A215918 _Zak Seidov_, Aug 27 2012