OFFSET
1,2
COMMENTS
Conjecture: the only odd term that occurs more than once is 1 = a(1) = a(4).
LINKS
FORMULA
a(1) = 1, and for n > 1, a(n) = -Sum_{d|n, d<n} (1+A048675(n/d)) * a(d).
For n >= 1, a(3^2n) = 4 and a(3^(2n+1)) = -4.
PROG
CROSSREFS
KEYWORD
sign
AUTHOR
Antti Karttunen, Jan 26 2023
STATUS
approved