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 A139405 #13 Mar 19 2020 06:54:41
%S A139405 2,5,9,12,24,29,32,44,54,57,74,75,80,107,110,122,129,137,152,162,165,
%T A139405 170,179,185,194,200,207,219,222,234,249,260,267,285,297,299,302,305,
%U A139405 332,339,362,414,432,452,470,500,509,519,555,557,564,570,582,584,599
%N A139405 Numbers k such that 8*k+1 and 8*k+7 are primes.
%H A139405 Amiram Eldar, <a href="/A139405/b139405.txt">Table of n, a(n) for n = 1..10000</a>
%t A139405 a = {}; Do[If[PrimeQ[8 n + 1] && PrimeQ[8 n + 7], AppendTo[a, n]], {n, 1, 1000}]; a
%Y A139405 Cf. A017077, A004771.
%Y A139405 Cf. A125821, A125822, A139402, A139404.
%K A139405 nonn
%O A139405 1,1
%A A139405 _Artur Jasinski_, Apr 19 2008