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 A006489 M4770 #59 Jul 02 2025 16:01:55
%S A006489 11,13,17,23,37,47,53,67,73,103,107,157,173,233,257,263,277,353,373,
%T A006489 563,593,607,613,647,653,733,947,977,1097,1103,1123,1187,1223,1283,
%U A006489 1297,1367,1433,1453,1487,1493,1607,1613,1663,1747,1753,1783,1867,1873
%N A006489 Numbers k such that k-6, k, and k+6 are primes.
%C A006489 A006562 without the first term 5 is a subsequence. - _Zak Seidov_, Apr 19 2021
%D A006489 N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
%H A006489 T. D. Noe, <a href="/A006489/b006489.txt">Table of n, a(n) for n = 1..1000</a>
%H A006489 Joseph Hirsch, <a href="http://www.jstor.org/stable/27958187">Prime Triplets</a>, Mathematics Teacher, 62 (1969), 467ff (see p. 471).
%H A006489 D. S. Kluk and N. J. A. Sloane, <a href="/A002050/a002050_3.pdf">Correspondence, 1979</a>
%t A006489 Select[Prime[Range[300]],And@@PrimeQ[#+{6,-6}]&] (* _Harvey P. Dale_, May 21 2012 *)
%o A006489 (Haskell)
%o A006489 a006489 n = a006489_list !! (n-1)
%o A006489 a006489_list = filter
%o A006489 ((== 1) . a010051 . (subtract 6)) $ dropWhile (<= 6) a023201_list
%o A006489 -- _Reinhard Zumkeller_, Feb 25 2013
%o A006489 (PARI) is(n)=isprime(n-6) && isprime(n) && isprime(n+6) \\ _Charles R Greathouse IV_, Feb 07 2017
%Y A006489 Subsequence of A023201.
%Y A006489 Cf. A006562.
%K A006489 nonn,nice,easy
%O A006489 1,1
%A A006489 _N. J. A. Sloane_
%E A006489 More terms from _James Sellers_, Dec 24 1999