OFFSET
0,3
COMMENTS
The ones in the binary representation of a(n) correspond to the digits "+1" in the balanced ternary representation of n.
We can extend this sequence to negative indices: a(-n) = A343229(n) for any n >= 0.
LINKS
Rémy Sigrist, Table of n, a(n) for n = 0..6561
Rémy Sigrist, Scatterplot of (a(n), A343229(n)) for n = 0..3^10
Wikipedia, Balanced ternary
EXAMPLE
The first terms, alongside the balanced ternary representation of n (with "T" instead of digits "-1") and the binary representation of a(n), are:
n a(n) ter(n) bin(a(n))
-- ---- ------ ---------
0 0 0 0
1 1 1 1
2 2 1T 10
3 2 10 10
4 3 11 11
5 4 1TT 100
6 4 1T0 100
7 5 1T1 101
8 4 10T 100
9 4 100 100
10 5 101 101
11 6 11T 110
12 6 110 110
13 7 111 111
14 8 1TTT 1000
15 8 1TT0 1000
PROG
(PARI) a(n) = { my (v=0, b=1, t); while (n, t=centerlift(Mod(n, 3)); if (t==+1, v+=b); n=(n-t)\3; b*=2); v }
CROSSREFS
KEYWORD
AUTHOR
Rémy Sigrist, Apr 08 2021
STATUS
approved