OFFSET
1,4
COMMENTS
Multiplicative because A003557 is.
No negative terms among the first 2^20 terms. Is the sequence nonnegative?
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..65537
Wikipedia, Dirichlet convolution
FORMULA
a(n) = numerator of f(n), where f(1) = 1, f(n) = (1/2) * (A003557(n) - Sum_{d|n, d>1, d<n} f(d) * f(n/d)) for n > 1.
PROG
CROSSREFS
KEYWORD
nonn,frac,mult
AUTHOR
Antti Karttunen, Aug 12 2018
STATUS
approved