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 A139402 #7 Mar 14 2020 05:05:23
%S A139402 2,5,17,71,101,107,131,491,677,761,821,1307,1361,1367,1667,2081,2207,
%T A139402 2837,3461,3467,3761,3767,4007,5087,5147,5231,5381,5927,6701,6737,
%U A139402 6917,6977,8447,8741,8807,9011,9341,9677,9767
%N A139402 Prime numbers k such that 8*k+1 and 8*k+3 are also primes.
%H A139402 Amiram Eldar, <a href="/A139402/b139402.txt">Table of n, a(n) for n = 1..10000</a>
%t A139402 a = {}; Do[If[PrimeQ[8 n + 1] && PrimeQ[8 n + 3] && PrimeQ[n],AppendTo[a, n]], {n, 1, 10000}]; a
%Y A139402 Cf. A125822.
%K A139402 nonn
%O A139402 1,1
%A A139402 _Artur Jasinski_, Apr 19 2008