%I A155890
%S A155890 2,12,21,102,120,201,210,1002,1020,1200,2001,2010,2100,10002,10020,
%T A155890 10200,12000,20001,20010,20100,21000,100002,100020,100200,102000,120000,
%U A155890 200001,200010,200100,201000,210000,1000002,1000020,1000200,1002000
%N A155890 a(n+1) is the least integer > a(n) containing all digits of a(n); a(1)=2.
%C A155890 We can easily show that : (1) All terms have digits less than 3. (2) 
               For m>1, a m-digit term of S has m-2 zero's, one 1 and one 2. (3) 
               For m>1, the set A(m) of m-digit terms of S has 2m-2 members and 
               A(m)=Join[Table[10^(m-1)+2*10^t,{t,0,m-2}],Table[2*10^(m-1)+10^t,
               {t,0,m-2}]] (4) For each m, at index n=m^2-m+2 number of digits of 
               a(n) equals to 1+number of digits of a(n-1). - F. Firoozbakht
%t A155890 /* Mmca code for generating all terms less than 10^m, m>1 (the first 
               m^2-m+1 terms) - by F. Firoozbakht */ n=m;A[n_]:=Join[Table[10^(n-1)+2*10^t,
               {t,0,n-2}], Table[2*10^(n-1)+10^t,{t,0,n-2}]]; v={2};Do[v=Join[v,
               A[k]],{k,2,n}];v
%Y A155890 Sequence in context: A058413 A053890 A053896 this_sequence A077410 A063599 
               A163479
%Y A155890 Adjacent sequences: A155887 A155888 A155889 this_sequence A155891 A155892 
               A155893
%K A155890 base,nonn
%O A155890 1,1
%A A155890 E. Angelini (Eric.Angelini(AT)kntv.be), F. Firoozbakht (f.firoozbakht(AT)sci.ui.ac.ir) 
               and M. F. Hasler (Maximilian.Hasler(AT)gmail.com), Feb 01 2009