This list is not the same every year. The topics are not necessarily in order.
Introduction to combinatorics.
Sections 1, 2, 4, 6 on various types of combinatorial problems.
All sections: basic counting, with and without repetition. Application to probability.
Sections 1-2, 4: Binomial identities, combinatorial proofs, binomial theorem.
Section 5: Multinomial theorem.
Sections 1-4: The Principle of Inclusion and Exclusion and a variety of ways to apply it, notably combinations with repetition, derangements, permutations with forbidden positions.
Sections 1, 3: Generating functions.
Sections 4-5: Recurrence relations.
Section 6: Application to a geometry problem.
Section 1: Catalan numbers.
Section 2: Difference sequences. Stirling numbers.
Sections 1-2: The pigeonhole principle.