There is a connection between the product of the Bell series of two functions and their Dirichlet convolution.
Theorem
Letand
be arithmetical functions and let
then for every prime
we have
Proof: Since the divisors ofare
we have
The last sum is the Cauchy product of the sequencesand
Examples:
so the Bell series of
modulo
is
so the Bell series of
modulo
is
Bell series can be used to investigate the properties of arithmetical functions. Ifwhere
and
then
is multiplicative and it's Bell series modulo
is
Hencewhich implies
or