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 A004618 #11 Oct 26 2023 00:42:11
%S A004618 1,19,29,59,79,89,109,139,149,179,199,229,239,269,349,359,361,379,389,
%T A004618 409,419,439,449,479,499,509,551,569,599,619,659,709,719,739,769,809,
%U A004618 829,839,841,859,919,929,1009,1019
%N A004618 Divisible only by primes congruent to 4 mod 5.
%H A004618 Vincenzo Librandi, <a href="/A004618/b004618.txt">Table of n, a(n) for n = 1..1000</a>
%t A004618 ok[1]=True;ok[n_]:=And@@(Mod[#,5]==4&)/@FactorInteger[n][[All,1]];Select[Range[4000],ok] (* _Vincenzo Librandi_, Aug 20 2012 *)
%o A004618 (Magma) [n: n in [1..1100] | forall{d: d in PrimeDivisors(n) | d mod 5 eq 4}]; // _Vincenzo Librandi_, Aug 20 2012
%K A004618 nonn,easy
%O A004618 1,2
%A A004618 _N. J. A. Sloane_