OFFSET
1,2
LINKS
Antti Karttunen, Table of n, a(n) for n = 1..65537
FORMULA
Multiplicative with a(p^e) = (e+1)*(p^(e-1)).
Dirichlet g.f.: zeta(s-1)^2 * Product_{p prime} (1 - 2/p^(s-1) + 2/p^s - 1/p^(2*s-1) + 1/p^(2*s-2)). - Amiram Eldar, Sep 14 2023
MATHEMATICA
f[p_, e_] := (e + 1)*p^(e - 1); a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* Amiram Eldar, Sep 14 2023 *)
PROG
CROSSREFS
KEYWORD
nonn,easy,mult
AUTHOR
Antti Karttunen, Sep 16 2018
STATUS
approved