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 A123978 #12 Mar 28 2020 04:28:01
%S A123978 2,5,80,107,110,185,260,332,500,1067,1307,1472,1625,1760,1790,1955,
%T A123978 2255,2612,2627,2672,2882,2945,3197,3335,3467,3965,4007,4037,4040,
%U A123978 4202,4355,4880,5147,5252,5525,6242,6812,6917,6977,7430,7787,8192,8612,8657,8720
%N A123978 Numbers k for which 8*k+1, 8*k+3 and 8*k+7 are primes.
%H A123978 Amiram Eldar, <a href="/A123978/b123978.txt">Table of n, a(n) for n = 1..10000</a>
%t A123978 Select[Range[10^4], And @@ PrimeQ /@ ({1, 3, 7} + 8#) &] (* _Ray Chandler_, Nov 05 2006 *)
%Y A123978 Cf. A005122, A005123, A005124.
%K A123978 nonn
%O A123978 1,1
%A A123978 _Artur Jasinski_, Oct 30 2006
%E A123978 Extended by _Ray Chandler_, Nov 05 2006