A362089 The base-3 expansion of a(n) is obtained by inserting a zero before each nonzero digit of the base-3 expansion of n.

0, 1, 2, 3, 10, 11, 6, 19, 20, 9, 28, 29, 30, 91, 92, 33, 100, 101, 18, 55, 56, 57, 172, 173, 60, 181, 182, 27, 82, 83, 84, 253, 254, 87, 262, 263, 90, 271, 272, 273, 820, 821, 276, 829, 830, 99, 298, 299, 300, 901, 902, 303, 910, 911, 54, 163, 164, 165, 496

Offset: 0

Author

Rémy Sigrist, Apr 08 2023

Keywords

• nonn
• base

Comments

This sequence is a permutation of A328727.

Examples

			The first terms, in decimal and in base-3, are:
  n   a(n)  ter(n)  ter(a(n))
  --  ----  ------  ---------
   0     0       0          0
   1     1       1          1
   2     2       2          2
   3     3      10         10
   4    10      11        101
   5    11      12        102
   6     6      20         20
   7    19      21        201
   8    20      22        202
   9     9     100        100
  10    28     101       1001
  11    29     102       1002
  12    30     110       1010
		

Crossrefs

Cf. A007089 (ter(n)), A048678, A328727, A362090.

Programs

PARI

a(n) = { if (n==0, 0, n%3, 9*a(n\3) + n%3, 3*a(n/3)); }

Python

from gmpy2 import digits
def A362089(n): return int(digits(n,3).replace('1','01').replace('2','02'),3)
# Chai Wah Wu, Apr 12 2023