05Axx Classical combinatorial problems
05A05 Combinatorial choice problems (subsets, representatives,
permutations)
05A10 Factorials, binomial coefficients, combinatorial functions,
See also {11B65, 33Cxx}
05A15 Exact enumeration problems, generating functions, See Also
{33Cxx, 33Dxx}
05A16 Asymptotic enumeration
05A17 Partitions of integers, See also {11P81, 11P82, 11P83}
05A18 Partitions of sets
05A19 Combinatorial identities
05A20 Combinatorial inequalities
05A30 $q$-calculus and related topics, See also {03Dxx}
05A40 Umbral calculus
05A99 None of the above but in this section