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 A120226 #15 Sep 27 2024 05:41:26
%S A120226 1,3,7,9,13,15,25,27,37,39,43,49,57,67,69,79,93,97,99,105,127,135,153,
%T A120226 163,169,175,177,189,193,207,219,235,253,265,267,273,277,279,303,307,
%U A120226 309,343,345,363,405,417,427,435,475,483,487,499,517,553,559,567,573
%N A120226 Numbers k such that 4+k and 4*k+1 are prime.
%C A120226 Except for 3, no terms == 3 or 5 (mod 7). - _Robert Israel_, Jul 26 2019
%H A120226 Robert Israel, <a href="/A120226/b120226.txt">Table of n, a(n) for n = 1..10000</a>
%p A120226 select(t -> isprime(t+4) and isprime(4*t+1), [seq(i,i=1..1000,2)]); # _Robert Israel_, Jul 26 2019
%t A120226 Select[Range[600],AllTrue[{4+#,4#+1},PrimeQ]&] (* _Harvey P. Dale_, Nov 14 2022 *)
%Y A120226 Cf. A092945, A106057, A085063, A120223, A120224, A120225, A120227.
%K A120226 nonn
%O A120226 1,2
%A A120226 _Zak Seidov_, Jun 10 2006