%I A050000
%S A050000 1,3,9,4,2,6,18,54,27,13,39,19,57,28,14,7,21,10,5,15,45,22,11,33,16,8,
%T A050000 24,12,36,108,324,162,81,40,20,60,30,90,270,135,67,201,100,50,25,75,37,
%U A050000 111,55,165,82,41,123,61,183,91,273,136,68
%N A050000 a(n)=[ a(n-1)/2 ] if this is not among 0,a(1),...,a(n-2), else a(n)=3*a(n-1).
%C A050000 This permutation of the natural numbers is the "MD sequence" for (M,D)=(3,
               2). The "MD question" is this: for relatively prime M and D, does 
               the MD sequence contain every positive integer exactly once? An affirmative 
               proof for the more general condition that log base D of M is irrational 
               is given by Mateusz Kwasnicki in Crux Mathematicorum 30 (2004) 235-239. 
               - Clark Kimberling (ck6(AT)evansville.edu), Jun 30 2004
%H A050000 T. D. Noe, <a href="b050000.txt">Table of n, a(n) for n=1..10000</a>
%H A050000 Clark Kimberling, <a href="http://faculty.evansville.edu/ck6/integer/
               unsolved.html">Unsolved Problems and Rewards</a>.
%Y A050000 Cf. A050076
%Y A050000 Sequence in context: A120982 A125143 A130701 this_sequence A154368 A161773 
               A021721
%Y A050000 Adjacent sequences: A049997 A049998 A049999 this_sequence A050001 A050002 
               A050003
%K A050000 nonn,nice,easy
%O A050000 1,2
%A A050000 Clark Kimberling (ck6(AT)evansville.edu)