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 A020459 #22 Sep 08 2022 08:44:45
%S A020459 2,7,227,277,727,2777,7727,22277,22727,22777,27277,72227,72277,72727,
%T A020459 272227,272777,727777,777277,2227727,2227777,2272727,2277727,2727727,
%U A020459 2772227,7272227,7722277,7727777,7772777,7777727,22227277,22272277
%N A020459 Primes that contain digits 2 and 7 only.
%H A020459 Alois P. Heinz, <a href="/A020459/b020459.txt">Table of n, a(n) for n = 1..20000</a> (first 1000 terms from Vincenzo Librandi)
%H A020459 James Maynard and Brady Haran, <a href="https://www.youtube.com/watch?v=eeoBCS7IEqs">Primes without a 7</a>, Numberphile video (2019)
%t A020459 Flatten[Table[Select[FromDigits/@Tuples[{2,7},n],PrimeQ],{n,8}]] (* _Vincenzo Librandi_, Jul 27 2012 *)
%o A020459 (Magma) [p: p in PrimesUpTo(22272277) | Set(Intseq(p)) subset [2, 7]]; // _Vincenzo Librandi_, Jul 27 2012
%Y A020459 Cf. A000040, A284921, A329760.
%K A020459 nonn,base
%O A020459 1,1
%A A020459 _David W. Wilson_