Comment by jmount

As a fan of combinatorics, I love people looking into the topic. Though most of what a programmer would find useful are approximations or trends which are handled well by the Master theorem ( https://en.wikipedia.org/wiki/Master_theorem_(analysis_of_al... ). For those deeply interested in the deep math of combinatorics I recommend Flajolet, Sedgewick, *Analytic Combinatorics, Cambridge 2009.