05Axx
03 | 
05 | 
05B 05Axx | 03 | 05 | 05B |
| 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 |