As cited above, I have made a "SymPy for smartphones & tablets" site :

http://www.robertocolistete.net/Python/SymPy/

Nokia N900 & Maemo 5 OS is clearly the best smartphone/tablet for SymPy/Python use. Nokia N8x0 & Maemo 4 OS and Nokia N9 & MeeGo Harmattan are also well ranked.

The above cite also summarizes how to install SymPy in mobile OS.

By the way, the Q4 2011 report from Canalys shows that 2011 was the year when smartphones shipped more than all the client PC's (pads, net/notebooks and desktops).

Maybe in 5 years timeframe Python (with SymPy, etc) will be more used in smartphonees & tablets than in PC's.