OFFSET
0,4
COMMENTS
For any v >= 0, the value v appears 2^A005811(v) times in the sequence.
LINKS
Rémy Sigrist, Table of n, a(n) for n = 0..6561
FORMULA
EXAMPLE
The first terms, alongside the ternary expansion of n and the binary expansion of a(n), are:
n a(n) ter(n) bin(a(n))
-- ---- ------ ---------
0 0 0 0
1 1 1 1
2 1 2 1
3 2 10 10
4 3 11 11
5 2 12 10
6 2 20 10
7 2 21 10
8 3 22 11
9 4 100 100
10 5 101 101
11 5 102 101
12 6 110 110
13 7 111 111
14 6 112 110
15 5 120 101
PROG
(PARI) a(n) = { my (r = [], d, l, v = 0); while (n, d = n%3; l = 0; while ((n%3)==d, n\=3; l++; ); r = concat(l, r); ); for (k = 1, #r, v = (v+k%2)*2^r[k]-k%2); v }
CROSSREFS
KEYWORD
nonn,base,easy
AUTHOR
Rémy Sigrist, Mar 16 2024
STATUS
approved