I am writing my masterthesis right now and after a few non-everyday equations, I was tired of searching for the right LaTeX command in Google to generate the proper math symbol.
But then I remembered a tool called “LaTeX symbol classifier” which link I have stored deep down in my bookmarks. With this, you just need to print the symbol with your mouse, and you will be pleased will the most probable commands in LaTeX.
This is a tool which shows IT at-it’s-best ;-). I’m wondering if they use HMMs for recognising like the Hanzi recognisers do.