%I A081857
%S A081857 0,1,1,3,11,23,111,223,1111,2223,11111,22223,111111,222223,1111111,
%T A081857 2222223,11111111,22222223,111111111,222222223,1111111111,2222222223,
%U A081857 11111111111,22222222223,111111111111,222222222223,1111111111111
%N A081857 Jacobsthal sequence (A001045) as represented in base 4.
%H A081857 Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/
               Repunit.html">Link to a section of The World of Mathematics.</a>
%F A081857 For n > 0, a(2n) is represented as a string of n 1's and a(2n+1) as a 
               string of (n-1) 2's followed by a 3.
%e A081857 a(8)= 1111 because A001045(8)= 85 (in base 10) = 64 + 16 + 4 + 1 = 1 
               * (4^3) + 1 * (4^2) + 1 * (4^1) + 1.
%Y A081857 Cf. A002450.
%Y A081857 Sequence in context: A158034 A002515 A096297 this_sequence A120088 A081737 
               A005475
%Y A081857 Adjacent sequences: A081854 A081855 A081856 this_sequence A081858 A081859 
               A081860
%K A081857 base,easy,nonn
%O A081857 0,4
%A A081857 Matthew Vandermast (ghodges14(AT)comcast.net), Apr 11 2003