Most of the problems are assigned from the required textbook Bona, Miklos. *A Walk Through Combinatorics: An Introduction to Enumeration and Graph Theory*. World Scientific Publishing Company, 2011. ISBN: 9789814335232. [Preview with Google Books]

A problem marked by * is difficult; it is not necessary to solve such a problem to do well in the course.

### Problem Set 2

- Due in Session 6
- Practice Problems
- Session 3: Chapter 3: Exercises 8, 9, 12, 18, 23, 24*
- Session 4: Chapter 4: Exercises 3, 13, 16, 26
- Session 5: Chapter 5: Exercises 6, 7, 8

- Problems Assigned in the Textbook
- Chapter 3: Exercises 38*, 41, 49. In my opinion Problem 38 does not deserve its (+), while 41 might need it.
- Chapter 4: Exercises 29, 39, 53*. Naturally in 53 you shouldn’t use a computer, calculator, etc.
**Hint**for 53: Consider also √11-√10. - Chapter 5: Exercises 23, 35 in 35, find a formula for _a_
_{n}in terms of Fibonacci numbers.

- Additional Problems
- (A1) Find the number _b_
_{n}of compositions of the positive integer*n*into odd parts. Express your answer in terms of Fibonacci numbers.

- (A1) Find the number _b_
- Bonus Problems
- None