OFFSET
0,3
COMMENTS
This sequence is a permutation of the nonnegative integers with inverse A321524.
LINKS
FORMULA
a(3 * n) = 3 * a(n).
EXAMPLE
The first terms, alongside the corresponding ternary representations, 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 7 12 21
6 6 20 20
7 5 21 12
8 8 22 22
9 9 100 100
10 10 101 101
11 19 102 201
12 12 110 110
13 13 111 111
14 16 112 121
15 21 120 210
16 22 121 211
17 25 122 221
PROG
(PARI) a(n, base=3) = my (d=digits(n, base), t=select(sign, d), i=0); for (j=1, #d, if (d[j], d[j]=t[1+(i++%#t)])); fromdigits(d, base)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Rémy Sigrist, Nov 13 2018
STATUS
approved