Hello, can anyone recommend good combinatorics textbooks for undergraduates? I will be teaching a 10-week course on the subject at Stanford, and I assume that the students will be strong and motivated but will not necessarily have background in subjects like abstract algebra or advanced calculus.

I intend to focus on the enumerative side of the subject and do permutations and combinations, generating functions, recurrence relations, Stirling and Catalan numbers, and related topics. However, this hasn't been set in stone and I also welcome advice for what topics to include.

I would be grateful if people would not only suggest names of books but also say a little bit about their merits. Thank you!