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 A004617 #19 Oct 26 2023 00:41:55
%S A004617 1,3,9,13,23,27,39,43,53,69,73,81,83,103,113,117,129,159,163,169,173,
%T A004617 193,207,219,223,233,243,249,263,283,293,299,309,313,339,351,353,373,
%U A004617 383,387,433,443,463,477,489,503
%N A004617 Divisible only by primes congruent to 3 mod 5.
%H A004617 Vincenzo Librandi, <a href="/A004617/b004617.txt">Table of n, a(n) for n = 1..1000</a>
%t A004617 ok[1] = True; ok[n_] := And@@ (Mod[#, 5] == 3&)/@ FactorInteger[n][[All,1]]; Select[Range[2000],ok] (* _Vincenzo Librandi_, Aug 11 2012 *)
%o A004617 (Magma) [n: n in [1..510] | forall{d: d in PrimeDivisors(n) | d mod 5 eq 3}]; // _Bruno Berselli_, Aug 11 2012
%K A004617 nonn
%O A004617 1,2
%A A004617 _N. J. A. Sloane_