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 A036943 #19 Aug 27 2022 12:51:15
%S A036943 3,83,383,3833,38333,333383,3333383,38383883,333388333,3333333833,
%T A036943 33333333833,333338838383,3333333333383,33333333888383,
%U A036943 333333333388883,3333333333838883,33333333333833383,333333333333333833
%N A036943 Smallest n-digit prime containing only the digits 3 and 8, or 0 if no such prime exists.
%H A036943 Jinyuan Wang, <a href="/A036943/b036943.txt">Table of n, a(n) for n = 1..500</a>
%t A036943 Table[SelectFirst[FromDigits[Join[#,{3}]]&/@Tuples[{3,8},n],PrimeQ],{n,0,20}] /.Missing["NotFound"]->0 (* _Harvey P. Dale_, Aug 27 2022 *)
%Y A036943 Cf. A020464, A036229, A036317.
%K A036943 nonn,base
%O A036943 1,1
%A A036943 _Patrick De Geest_, Jan 04 1999