A050076 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).

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, 576, 192, 384, 128, 42, 84, 168, 56, 112, 37, 74, 148, 49, 98, 196, 65, 130, 43, 86, 172, 57, 19, 38, 76, 25, 50, 100, 33, 11, 22, 44, 88, 29, 58

Offset: 1

Author

Clark Kimberling

Keywords

• nonn

Comments

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

Links

• T. D. Noe, Table of n, a(n) for n = 1..10000
• Clark Kimberling, Unsolved Problems and Rewards.

Crossrefs

Cf. A050000 and references therein.

Programs

Mathematica

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