Another option that I used to write my lecture notes in is DokuWiki. Simple syntax in general and you can embed LaTeX for formulas. I used a Lenovo x-series tab

Another option that I used to write my lecture notes in is DokuWiki. Simple syntax in general and you can embed LaTeX for formulas. I used a Lenovo x-series tablet, so I also had a stylus to quickly draw diagrams in Gimp, and the keyboard was nice too. I'd use Emacs org-mode now unless the Wiki made was needed to work on with others.