For
, Bernoulli and Euler polynomials of order
are defined respectively by


When
they reduce to the Bernoulli and Euler numbers of
order
:
Also for
,

For this and other properties see Milne-Thomson (1933, pp. 126–153) or Nörlund (1924, pp. 144–162).
For extensions of
to complex values of
,
, and
, and also for uniform asymptotic expansions for large
and large
,
see Temme (1995b).

For sufficiently small
,

Here
again denotes the Stirling number of the first kind.

is a polynomial in
of degree
. (This notation is
consistent with (24.16.3) when
.)
Let
be a primitive Dirichlet character
(see §27.8).
Then
is called the conductor of
. Generalized Bernoulli
numbers and polynomials belonging to
are defined by
Let
be the trivial character and
the unique (nontrivial)
character with
; that is,
,
,
. Then
For further properties see Berndt (1975a).
In no particular order, other generalizations include: Bernoulli numbers and
polynomials with arbitrary complex index (Butzer et al. (1992)); Euler
numbers and polynomials with arbitrary complex index (Butzer et al. (1994));
q-analogs (Carlitz (1954b), Andrews and Foata (1980)); conjugate
Bernoulli and Euler polynomials (Hauss (1997, 1998));
Bernoulli–Hurwitz numbers (Katz (1975)); poly-Bernoulli numbers
(Kaneko (1997)); Universal Bernoulli numbers
(Clarke (1989));
-adic integer order Bernoulli numbers
(Adelberg (1996));
-adic
-Bernoulli numbers
(Kim and Kim (1999)); periodic Bernoulli numbers (Berndt (1975b));
cotangent numbers (Girstmair (1990b)); Bernoulli–Carlitz numbers
(Goss (1978)); Bernoulli-Padé numbers (Dilcher (2002));
Bernoulli numbers belonging to periodic functions
(Urbanowicz (1988)); cyclotomic Bernoulli numbers
(Girstmair (1990a)); modified Bernoulli numbers
(Zagier (1998)); higher-order Bernoulli and Euler polynomials with
multiple parameters (Erdélyi et al. (1953a, §§1.13.1, 1.14.1)).