A137305 Write n in base 3, change twos in ones and ones in twos, reverse.

0, 2, 1, 2, 8, 5, 1, 7, 4, 2, 20, 11, 8, 26, 17, 5, 23, 14, 1, 19, 10, 7, 25, 16, 4, 22, 13, 2, 56, 29, 20, 74, 47, 11, 65, 38, 8, 62, 35, 26, 80, 53, 17, 71, 44, 5, 59, 32, 23, 77, 50, 14, 68, 41, 1, 55, 28, 19, 73, 46, 10

Offset

0,2

Comments

This is not to A036044 as A007089 is to A007088: despite similarity here the operation performed is not a base 3 complement. Fixed points begin: 5, 7, 11, 19, 29, 44, 50, 55.

Links

Alois P. Heinz, Table of n, a(n) for n = 0..6561

Formula

a(3^n) = 2. a(2*3^n) = 1.

Example

53 -> 1222 -> 2111 -> 1112 -> 41.

Maple

a:= proc(n) local m, r; m, r:= n, 0; while m>0
      do r:=r*3+[0, 2, 1][1+irem(m, 3, 'm')] od; r
    end:
seq(a(n), n=0..100);  # Alois P. Heinz, Jun 20 2016

Mathematica

a[n_] := FromDigits[ Reverse[ IntegerDigits[n, 3] /. {1 -> 2, 2 -> 1}], 3] (* Giovanni Resta, Jun 20 2016 *)

Crossrefs

Cf. A007089, A036044.

Sequence in context: A334729 A221878 A219109 * A282885 A242841 A143208

Adjacent sequences: A137302 A137303 A137304 * A137306 A137307 A137308

Keyword

base,easy,nonn

Author

Jonathan Vos Post, Apr 20 2008

Extensions

Edited and corrected by Giovanni Resta, Jun 20 2016

Status

approved