Through teaching, I’ve occasionally written good stand-alone notes. Many can be found by browsing the teaching category here. Some which I find particularly good are noted below.

• An Intuitive Introduction to Calculus
• An Intuitive Overview of Taylor Series
• A Brief Notebook on Cryptography
• Notes from a Talk on the Mean Value Theorem
• A first and second supplemental set of notes on the Gaussian integers
• A Friendly Introduction to Sieves, with a Look Towards Recent Results
• A short note on common, but oft-forgotten properties of the gamma and beta functions