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A137305 Write n in base 3, change twos in ones and ones in twos, reverse. 1
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified October 16 20:36 EDT 2021. Contains 348047 sequences. (Running on oeis4.)