I'm looking for a textbook recommendation for a first course in combinatorics that is purely focused on theoretical mathematics. Most of the books I've come across tend to have a significant emphasis on computer science or various applications, but I'm specifically interested in a text that delves into the foundational theory without any practical applications.
I familiar with Linear algebra, Real analysis, ODE, Calculus and Complex analysis. I also done many rigorous proofs so I am familiar with rigorous math books. Are there any prerequisites that I need?