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 A270037 #11 Mar 10 2016 20:54:51
%S A270037 4,5,7,7,13,13,13,13,13,13,23,23,23,23,23,23,23,23,23,23,43,43,43,43,
%T A270037 43,43,43,43,43,43,43,43,43,43,43,43,43,43,43,43,157,157,157,157,157,
%U A270037 157,157,157,157,157,157,157,157,157,157,157,157,157,157,157,157,157,157
%N A270037 a(n) = Smallest m >= 3 containing no zeros when represented in any base from 3 through n.
%C A270037 It remains to be determined if the sequence is finite.
%C A270037 Every known term in this sequence is in A069575, and every term in A069575 is in this sequence.
%H A270037 Nathan Fox, <a href="/A270037/b270037.txt">Table of n, a(n) for n = 3..618</a>
%t A270037 Table[SelectFirst[Range[3, 10^3], Total@ Map[Function[k, DigitCount[#, k, 0]], Range[3, n]] == 0 &], {n, 3, 80}] /. n_ /; MissingQ@ n -> Nothing (* _Michael De Vlieger_, Mar 10 2016, Version 10.2 *)
%o A270037 (PARI) isok(m, n) = {for (b=3, n, if (! vecmin(digits(m, b)), return (0));); 1;}
%o A270037 a(n) = {my(m = 3); while (! isok(m,n), m++); m;} \\ _Michel Marcus_, Mar 10 2016
%Y A270037 Cf. A069575, A270027, A270038, A216192, A270039, A270040, A270041, A270042, A270043, A270044, A270045.
%K A270037 nonn,base
%O A270037 3,1
%A A270037 _Nathan Fox_, Mar 09 2016