OFFSET
1,2
COMMENTS
Not multiplicative because A318317 contains zeros.
Differs from A317926 at n = 200, 400, 600, 800, 900, 1200, 1400, 1600, 1800, 2200, 2400, 2700, 2800, 3200, 3600, 3800, 4050, 4200, 4400, 4600, 4800, 4900, 5200, ..., which seem to be a subsequence of positions of zeros in A318317.
Here a(200) = 1, while A317926(200) = 2.
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..65537
FORMULA
a(n) = denominator of f(n), where f(1) = 1, f(n) = (1/2) * (A173557(n) - Sum_{d|n, d>1, d<n} f(d) * f(n/d)) for n > 1.
PROG
CROSSREFS
KEYWORD
nonn,frac
AUTHOR
Antti Karttunen, Aug 24 2018
STATUS
approved