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 A209930 #16 Jul 16 2014 15:34:53
%S A209930 1,11,101,1111,10111,101111,1011001,1100101,10010101,10011101,
%T A209930 10100011,10101101,10110011,10111001,11000111,11100101,11110111,
%U A209930 11111101,100100111,100111001,101001001,101001011,101100011,101101111,101111011,101111111,110010101
%N A209930 Numbers n such that largest digit of all divisors of n is 1.
%C A209930 Also numbers n such that largest digit of concatenation of all divisors (A037278) of n is 1.
%C A209930 What is the smallest n with a(n) <> A203304(n)? - _Alois P. Heinz_, Jul 16 2014
%H A209930 Alois P. Heinz, <a href="/A209930/b209930.txt">Table of n, a(n) for n = 1..8503</a>
%e A209930 Number 1111 is in sequence because largest digit of all divisors of 1111 (1, 11, 101, 1111) is 1.
%t A209930 t = {}; n = 0; While[Length[t] < 30, n++; m = FromDigits[IntegerDigits[n, 2]]; If[Max[Union[Flatten[IntegerDigits[Divisors[m]]]]] <= 1, AppendTo[t, m]]]; t (* _T. D. Noe_, Jan 30 2013 *)
%Y A209930 Cf. A209928 (largest digit of all divisors of n).
%Y A209930 Cf. A203304.
%K A209930 nonn,base
%O A209930 1,2
%A A209930 _Jaroslav Krizek_, Mar 20 2012
%E A209930 Corrected by _Jaroslav Krizek_, Jan 29 2013