From what I've seen online, it looks like the pow() function should take an optional third argument, so that pow(a,b,m) would return (a**b)%m. But this isn't working. When I try to pass three ...

You would be very hard pressed to find any sort of CPU or microcontroller in a commercial product that uses anything but binary to do its work. And yet, other options exist! Ternary computing involves ...