Search: id:A050000 Results 1-1 of 1 results found. %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, Table of n, a(n) for n=1..10000 %H A050000 Clark Kimberling, Unsolved Problems and Rewards. %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) Search completed in 0.001 seconds