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 (1954a), 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)).