It's been a while since I got to use a functional language, I did a lot of training on scala, but never really used F#, so I gave it a go with the FizzBuzz kata.
The rules for FizzBuzz are simple:
Write a program that prints the numbers from 1 to 100. But for multiples of three print "Fizz" instead of the number and for the multiples of five print "Buzz". For numbers which are multiples of both three and five print "FizzBuzz".
Its a nice easy challenge when writing in an unfamiliar language, especially when trying to do things properly (TDD)