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 A216192 #25 Mar 18 2016 03:30:51
%S A216192 9,12,28,28,28,28,28,31
%N A216192 a(n) = Smallest m >= 5 containing no twos when represented in any base from 3 through n.
%C A216192 If a(11) exists, it contains over 3000 digits.
%C A216192 No more terms < 10^154400. Most likely there are no more terms. - _Chai Wah Wu_, Mar 17 2016
%H A216192 Nathan Fox, <a href="/A216192/a216192.txt">Maple Program to compute a(n)</a>
%e A216192 In base 3, 5=12, 6=20, 7=21, 8=22, 9=100. The first representation containing no twos is that of 9, so a(3)=9.
%t A216192 Table[SelectFirst[Range[5, 10^3], Total@ Map[Function[k, DigitCount[#, k, 2]], Range[3, n]] == 0 &], {n, 3, 20}] /. n_ /; MissingQ@ n -> Nothing (* _Michael De Vlieger_, Mar 09 2016, Version 10.2 *)
%Y A216192 Cf. A216194, A270037, A270038, A270039, A270040, A270041, A270042, A270043, A270044, A270045.
%K A216192 nonn,hard,more,base
%O A216192 3,1
%A A216192 _Nathan Fox_, Mar 12 2013