Hello adorkisme!
If you have started to code, post the code (using the [#] button when posting) this way it will be easier for us to see what we can help / contribute with. If you have no code, or no idea how to implement a thing like this:
Break it up into smaller problems.
Play with division. http://arduino.cc/en/Reference/Arithmetic
Familiarize with division on bytes and ints and the modulo http://arduino.cc/en/Reference/Modulo as well as division on floats / doubles.
Try to capture input. http://arduino.cc/en/Reference/PulseIn
Try to log a series of inputs. http://arduino.cc/en/Reference/Array
Try to accomplish a hardcoded version of your output. So you'll know what it takes.http://arduino.cc/en/Reference/For
I would love to help out, but it is hard when I do not know more about the problem 