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 A020453 #22 May 21 2025 01:38:08
%S A020453 5,11,151,1151,1511,11551,15511,15551,51151,51511,51551,55511,115151,
%T A020453 511111,511151,515111,1111151,1115551,1155151,1551551,1555111,5115511,
%U A020453 5151151,5151551,5155511,5511151,5511511,5515151,5551111,15511151
%N A020453 Primes that contain digits 1 and 5 only.
%C A020453 The first 8 terms are also primes when read backward, i.e. in A007500. See also A199325. - M. F. Hasler, Nov 05 2011
%H A020453 Jason Bard, <a href="/A020453/b020453.txt">Table of n, a(n) for n = 1..10000</a> (terms 1..1000 from Vincenzo Librandi)
%t A020453 Flatten[Table[Select[FromDigits/@Tuples[{1,5},n],PrimeQ],{n,7}]] (* _Vincenzo Librandi_, Jul 27 2012 *)
%o A020453 (PARI) {L=[1,5];for(d=1,9,u=vector(d,i,10^(d-i))~;forvec(v=vector(d,i,[1,#L]),ispseudoprime(t=vector(d,i,L[v[i]])*u)&print1(t",")))} \\ _M. F. Hasler_, Nov 05 2011
%Y A020453 Subsequence of A030096.
%K A020453 nonn,base
%O A020453 1,1
%A A020453 _David W. Wilson_