

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
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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



