Ask HN: Online Master's in Mathematics

I have a BS in Math & CS and have been working as a software engineer for 10+ years, but I miss math. I realize I can study on my own, but I like the direction an academic program can provide, and I'd like the option to teach or pursue a PhD later.

There are many online Master's degrees for CS and Mathematics Education (for secondary Ed teachers), but I'm interested in an online MS/MA in Mathematics that is as rigorous & theory-heavy as possible.

These are the programs I'm considering - am I missing anything? Can anyone speak to the strengths of these programs?

Emporia State University: https://www.emporia.edu/mathecon/programs/master-of-science-mathematics.html

Open University: http://www.openuniversity.edu/courses/postgraduate/qualifications/f04

Also considering NC State's statistics program since the school is well-regarded and has many flexible options:

https://online.stat.ncsu.edu/online-programs/online-graduate-statistics-courses/