login
A358935
a(n) is the least k > 0 such that fusc(n) = fusc(n + k) or fusc(n) = fusc(n - k) (provided that n - k >= 0), where "fusc" is Stern's diatomic series (A002487).
1
1, 1, 3, 2, 2, 3, 2, 4, 6, 3, 2, 6, 2, 4, 3, 8, 4, 3, 4, 6, 6, 4, 2, 12, 2, 4, 6, 8, 4, 6, 3, 16, 30, 3, 12, 6, 4, 8, 18, 12, 4, 12, 10, 8, 6, 4, 2, 24, 2, 4, 6, 8, 10, 12, 4, 16, 18, 7, 4, 12, 9, 6, 3, 32, 7, 3, 7, 6, 12, 9, 8, 12, 46, 7, 12, 11, 12, 21, 7
OFFSET
1,3
COMMENTS
Every positive integer appears infinitely many times in A002487, hence the sequence is well defined.
FORMULA
a(2^k) = 2^(k-1) for any k > 0.
a(n) = 2 iff n belongs to A097581 \ {2}.
EXAMPLE
The first terms, alongside fusc(n) and the direction where to find the same value, are:
n a(n) fusc(n) dir
-- ---- ------- ---
1 1 1 +
2 1 1 -
3 3 2 +
4 2 1 -
5 2 3 +
6 3 2 -
7 2 3 -
8 4 1 -
9 6 4 +
10 3 3 -
11 2 5 +
12 6 2 -
PROG
(PARI) See Links section.
CROSSREFS
Sequence in context: A248138 A049234 A299351 * A294299 A125504 A243929
KEYWORD
nonn
AUTHOR
Rémy Sigrist, Dec 07 2022
STATUS
approved