%I A124245
%S A124245 1,3,25,101,363,3125,15625,71023,390625,1183713,5474669,27151397,
%T A124245 135646011,1220703125,6103515625,18480090517,85533990571,762939453125,
%U A124245 3814697265625,11550150977337,53458791308981,265147974756053
%N A124245 a(n) is the smallest odd number m such that 2^n*m has n digits but has 
               at most two distinct digits.
%C A124245 For each n, a(n) exists and is <= 5^(n-1).
%H A124245 The Prime Puzzles & Problems Connection, <a href="http://www.primepuzzles.net/
               puzzles/puzz_376.htm">Puzzle 376. n=p*2^x</a>.
%e A124245 a(13)=135646011 because 2^13*135646011=1111212122112 has 13 digits with 
               two distinct digits and 135646011 is the smallest odd number m such 
               that 2^13*m has these properties.
%t A124245 a[1]=1;a[n_]:=(For[m=Floor[5^(n-1)/4],!(Length[Union[IntegerDigits [2^n*(2m-1)]]]==2&&Length[IntegerDigits[2^\
               n*(2m-1)]]==n),m++ ];2m-1 );Do[Print[a[n]],{n,14}]
%Y A124245 Cf. A124244.
%Y A124245 Sequence in context: A041565 A114378 A075306 this_sequence A059457 A165206 
               A095664
%Y A124245 Adjacent sequences: A124242 A124243 A124244 this_sequence A124246 A124247 
               A124248
%K A124245 nonn,base
%O A124245 1,2
%A A124245 Farideh Firoozbakht (mymontain(AT)yahoo.com), Oct 27 2006
%E A124245 Edited by Don Reble (djr(AT)nk.ca), Oct 29 2006