Create freqseq.py

Author- Travis Boettjer
    
    Run this as a python file in the command prompt or python executor as such 'python freqseq.py' and example will run
    
    
    
    Average runtime: O(n)
        This is because there is one for loop and the rest of the actions are constant time
    Space complexity: O(n)
        This is because the dictionary uses O(n) because most hashmap functions are O(n)
    
    Worst Case runtime: O(n)
        For the same reason
    Worst Case Space Complexity: O(n)
        For the same reason