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 A038105 #13 May 17 2019 02:34:30
%S A038105 0,1,2,3,4,10000,10001,10002,10003,10004,20000,20001,20002,20003,
%T A038105 20004,30000,30001,30002,30003,30004,40000,40001,40002,40003,40004,
%U A038105 124343,124401,130000,130001,130002,130003,130004,132114,210000,210001,210002
%N A038105 Numbers n with property that n is a substring of its base 5 representation.
%H A038105 Giovanni Resta, <a href="/A038105/b038105.txt">Table of n, a(n) for n = 1..445</a> (terms < 10^15)
%e A038105 124343 = base 10 -> {124343}33 = base 5.
%Y A038105 Cf. A038102-A038106, A228050-A228052, A227549.
%K A038105 nonn,base
%O A038105 1,3
%A A038105 _Patrick De Geest_, Feb 15 1999