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 A086818 #4 Mar 30 2012 17:29:07 %S A086818 111,1011,1101,1110,10011,10101,10110,11001,11010,100011,100101, %T A086818 100110,101001,101010,110001,110010,1000011,1000101,1000110,1001001, %U A086818 1001010,1010001,1010010,1100010,10000011,10000101,10000110,10001001,10001010 %N A086818 a(1) = 111, a(n) = the smallest squarefree number > a(n-1) which contains all the digits of a(n-1). %C A086818 Conjecture: Terms contain exactly three 1's digits and the rest 0's digits. %Y A086818 Cf. A077712. %K A086818 base,nonn %O A086818 1,1 %A A086818 _Ray Chandler_, Aug 06 2003