Looking for discrete mathematics book

Question

I'm looking for a book I read some time ago and I forgot the title/authors.
It is a large book about 600 pages and was introductory to discrete mathematics. The first chapter was about falling/rising factorials and closed form for solving linear recursions.
Could someone direct me to it?

Answer 1

Finally found it!!!! https://en.wikipedia.org/wiki/Concrete_Mathematics placeholder text