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 A039938 #16 Apr 27 2017 23:06:38
%S A039938 7,37,237,1789,4357,14379,19587,93957,189572,189572,189597,189597,
%T A039938 189597,1234397,1839597,1958798,1983957,1983957,1983957,1983957,
%U A039938 1983957,1983957,3978594,11983957,19596487,29195397,29195397,29195397
%N A039938 Smallest k for which k, 2k, ... nk all contain the digit 7.
%H A039938 Giovanni Resta, <a href="/A039938/b039938.txt">Table of n, a(n) for n = 1..125</a>
%e A039938 a(2)=37 since 37 and 74 contain a 7.
%t A039938 Table[SelectFirst[Range[10^6], Times @@ Boole@ Map[DigitCount[#, 10, 7] > 0 &, # Range@ n] > 0 &], {n, 12}] (* _Michael De Vlieger_, Apr 27 2017, Version 10 *)
%Y A039938 Cf. A039932, A039933, A039934, A039935, A039936, A039937, A039939, A039940.
%K A039938 base,nonn
%O A039938 1,1
%A A039938 _Erich Friedman_
%E A039938 More terms from _Patrick De Geest_, Oct 15 1999