OFFSET
1,4
COMMENTS
This is not multiplicative. The first point where a(m*n) = a(m)*a(n) does not hold for coprime m and n is 1444 = 2^2 * 19^2, where a(1444) = 181 <> 5*181 = a(4)*a(361). See A348740 for the list of such positions.
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..21125
MATHEMATICA
f[p_, e_] := (p + 1)^e/(p^e + 1); a[1] = 1; a[n_] := Denominator[Times @@ f @@@ FactorInteger[n]]; Array[a, 100] (* Amiram Eldar, Nov 05 2021 *)
PROG
CROSSREFS
KEYWORD
nonn,frac
AUTHOR
Antti Karttunen, Nov 05 2021
STATUS
approved