OFFSET
0,3
COMMENTS
This sequence is a permutation of the nonnegative integers with inverse A353827.
A number is a fixed point of this sequence iff it has at most one digit 2 in its ternary expansion, that digit 2 being its leftmost nonzero digit.
LINKS
FORMULA
a(3*n) = 3*a(n).
a(3*n + 1) = 3*a(n) + 1.
EXAMPLE
The first terms, in decimal and in ternary, 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 4 11 11
5 8 12 22
6 6 20 20
7 7 21 21
8 5 22 12
9 9 100 100
10 10 101 101
11 20 102 202
12 12 110 110
PROG
(PARI) a(n) = { my (d=digits(n, 3), p=1); forstep (k=#d, 1, -1, if (d[k], d[k]=p*=d[k])); fromdigits(d%3, 3) }
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Rémy Sigrist, May 08 2022
STATUS
approved