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 A140555 #18 Jun 14 2017 01:06:47 %S A140555 2,3,19,29,43,59,71,79,89,109,113,127,137,139,149,163,179,181,197,199, %T A140555 211,229,239,241,269,281,283,293,313,317,337,349,359,379,389,397,401, %U A140555 409,419,421,431,439,449,463,467,479,487,491,499,509,521,523,547,569 %N A140555 Primes p such that p + 6 is not a prime. %C A140555 Note that if Goldbach's Conjecture (2n = p1 + p2 for all n>=2) is false and K is the smallest value of n for which it fails, then for 2(K-3) = p3 + p4, the primes p3 and p4 must be taken from this list. See also A067775. - Keith Backman, Apr 05 2012 %H A140555 Zak Seidov, <a href="/A140555/b140555.txt">Table of n, a(n) for n = 1..10000</a> %F A140555 A000040 SET MINUS A023201. - _R. J. Mathar_, Aug 09 2008 %t A140555 Select[Prime[Range[200]],!PrimeQ[#+6]&] (* _Harvey P. Dale_, Dec 21 2016 *) %o A140555 (PARI) forprime(p=2,600,if(!isprime(p+6),print1(p,","))) \\ _Klaus Brockhaus_, Aug 12 2008 %Y A140555 Cf. A000040, A023201, A067775. %K A140555 nonn %O A140555 1,1 %A A140555 _Juri-Stepan Gerasimov_, Jul 03 2008 %E A140555 Corrected by _R. J. Mathar_ and _Klaus Brockhaus_, Aug 12 2008