OFFSET
1
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..107163
FORMULA
a(1) = 1, and for n > 1, a(n) = -Sum_{d|n, d<n} A336923(n/d) * a(d).
Multiplicative with a(2^e) = -1 if e = 1, and 0 if e > 1, and for primes p > 2, a(p^e) = (-A036987(p))^e. - Corrected by Amiram Eldar and Antti Karttunen, Jan 24 2023
MATHEMATICA
f[p_, e_] := If[2^IntegerExponent[p + 1, 2] == p + 1, (-1)^e, 0]; f[2, e_] := If[e == 1, -1, 0]; a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* Amiram Eldar, Jan 24 2023 *)
PROG
CROSSREFS
KEYWORD
sign,mult
AUTHOR
Antti Karttunen, Jan 08 2023
STATUS
approved