OFFSET
1,4
COMMENTS
Möbius transform of A252748.
LINKS
FORMULA
MATHEMATICA
f[p_, e_] := NextPrime[p]^e; s[1] = 1; s[n_] := Times @@ f @@@ FactorInteger[n]; a[n_] := EulerPhi[s[n]] - 2*EulerPhi[n]; Array[a, 100] (* Amiram Eldar, Dec 04 2021 *)
PROG
CROSSREFS
KEYWORD
sign
AUTHOR
Antti Karttunen, Dec 01 2021
STATUS
approved