Note to study group participants:
I've uploaded a new version of the Review notebook with corrections for a few typos and missing things. Please find it at the same folder!
I've also added the "Hamiltonian Mechanics" Manipulate example notebook that I showed, for the interested reader.
Lastly, I found the function I was looking for that can find generating functions for particular integer sequences—it's the rather obviously-named, in retrospect, FindSequenceFunction. I did scroll past it in the documentation when we were looking for it, but just glossed over it. It's neat!