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 A199718 #21 Mar 20 2023 12:44:19 %S A199718 5,9,10,15,23,25,29,30,32,40,42,43,44,45,49,58,60,65,70,72,75,80,85, %T A199718 87,93,94,95,98,99,100,107,109,110,114,117,120,133,135,137,140,155, %U A199718 158,159,163,164,170,172,175,177,184,185,192,194,197,198,199,204,205 %N A199718 Numbers k such that 6*k-5 is composite, but 6*k-1 is prime. %H A199718 Vincenzo Librandi, <a href="/A199718/b199718.txt">Table of n, a(n) for n = 1..1000</a> %t A199718 Select[Range[2, 205], ! PrimeQ[6 # - 5] && PrimeQ[6 # - 1] &] (* _T. N. Noe_, Nov 09 2011 *) %o A199718 (Magma) [ p div 6 +1: n in [4..204] | not IsPrime(p-4) and p mod 6 eq 5 where p is NthPrime(n) ]; // _Bruno Berselli_, Nov 09 2011 %Y A199718 Cf. A186243. %K A199718 nonn,easy %O A199718 1,1 %A A199718 _Eleonora Echeverri-Toro_, Nov 09 2011