A050076 - OEIS

%I #21 Oct 05 2019 11:26:51

%S 1,2,4,8,16,5,10,3,6,12,24,48,96,32,64,21,7,14,28,9,18,36,72,144,288,

%T 576,192,384,128,42,84,168,56,112,37,74,148,49,98,196,65,130,43,86,

%U 172,57,19,38,76,25,50,100,33,11,22,44,88,29,58

%N a(n) = floor(a(n-1)/3) if this is not among 0, a(1), ..., a(n-2); otherwise a(n) = 2*a(n-1).

%C This permutation of the natural numbers is the "MD sequence" for (M,D) = (2,3). See A050000. - _Clark Kimberling_, Jun 30 2004

%H T. D. Noe, <a href="/A050076/b050076.txt">Table of n, a(n) for n = 1..10000</a>

%H Clark Kimberling, <a href="http://faculty.evansville.edu/ck6/integer/unsolved.html">Unsolved Problems and Rewards</a>.

%t Rest@Nest[Append[#, If[FreeQ[#, r = Quotient[#[[-1]], 3]], r, 2 #[[-1]]]] &, {0, 1}, 60] (* _Ivan Neretin_, Jul 31 2016 *)

%Y Cf. A050000 and references therein.

%K nonn

%O 1,2

%A _Clark Kimberling_