OFFSET
1,2
COMMENTS
LINKS
FORMULA
a(n) = Sum_{d|n} d * A003972(n/d).
Multiplicative with a(p^e) = q(p)^e + (p-1)*(q(p)^e - p^e)/(q(p) - p), where q(p) = nextprime(p) = A151800(p). - Amiram Eldar, Sep 16 2023
MATHEMATICA
f[p_, e_] := (q = NextPrime[p])^e + (p - 1)*(q^e - p^e)/(q - p); a[1] = 1; a[n_] := Times @@ f @@@ FactorInteger[n]; Array[a, 100] (* Amiram Eldar, Sep 16 2023 *)
PROG
CROSSREFS
KEYWORD
nonn,easy,mult
AUTHOR
Antti Karttunen, Aug 24 2021
STATUS
approved