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 A124408 #6 Aug 04 2019 05:40:06
%S A124408 1,3,18,105,135,153,165,168,300,363,585,618,648,765,828,1110,1140,
%T A124408 1278,1518,1530,1533,2130,2223,2400,2475,2613,2790,2925,3075,3180,
%U A124408 3345,3420,3483,3810,3840,3843,3933,4008,4083,4095,4143,4260,4263,4323,4470,4545
%N A124408 Numbers k such that 2k+1, 4k+1 and 6k+1 are primes.
%H A124408 Jinyuan Wang, <a href="/A124408/b124408.txt">Table of n, a(n) for n = 1..10000</a>
%t A124408 Select[Range[4600], And @@ PrimeQ /@ ({2, 4, 6}*# + 1) &] (* _Ray Chandler_, Nov 20 2006 *)
%o A124408 (PARI) is(k) = sum(j = 1, 3, isprime(2*j*k+1)) == 3; \\ _Jinyuan Wang_, Aug 04 2019
%Y A124408 Cf. A005097, A005098, A024899, A123998, A124409, A124410, A124411, A071576.
%K A124408 nonn
%O A124408 1,2
%A A124408 _Artur Jasinski_, Oct 31 2006