Given a sequence , a formal
power series
(1)
| |||
(2)
|
is called the Dirichlet generating function of the sequence (Wilf 1994, p. 56).
The Dirichlet generating function of a sequence can be found in the Wolfram
Language using DirichletTransform[a[n],
n, s].
The following table summarizes the sequences generated by a number of functions. For example, gives the sequence of all 1s, while
gives the sequence of the number of divisors
,
where
is the zeroth order divisor function. In the
table,
is the Möbius function,
is the number of ordered
factorizations,
is the totient function,
is the Dirichlet lambda function,
is the Dedekind function, and
is the prime zeta function.
In general,
generates the number of ordered
factorizations of
into
factors (Wilf 1994, p. 58).
OEIS | sequence | ||
A008683 | 1, | ||
1 | 1, 1, 1, 1, 1, 1, 1, 1, ... | ||
A000005 | 1, 2, 2, 3, 2, 4, 2, 4, ... | ||
A000010 | 1, 1, 2, 2, 4, 2, 6, 4, 6, 4, 10, ... | ||
A002033 | 1, 1, 1, 2, 1, 3, 1, 4, 2, 3, 1, 8, ... | ||
A000035 | 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, 1, 0, ... | ||
A001615 | 1, 3, 4, 6, 6, 12, 8, 12, 12, 18, 12, ... | ||
cubefree
part of | A050985 | 1, 2, 3, 4, 5, 6, 7, 1, 9, 10, 11, 12, ... | |
characteristic
function of the prime numbers | A000000 | 0, 1, 1, 0, 1, 0, 1, 0, 0, 0, 1, 0, 1, ... | |
characteristic
function of the composite numbers | A000000 | 0, 0, 0, 1, 0, 1, 0, 1, 1, 1, 0, 1, 0, ... |
If
and
are Dirichlet generating functions of two sequences
and
respectively such that the two sequences are
connected by
(3)
|
for .
Then
(4)
|
and the sequences are related by the Möbius inversion formula
(5)
|
where
is the Möbius function (Wilf 1994, p. 62).