def fb(n):
    """Return a list of strings for numbers 1..n with FizzBuzz rules.
    Multiples of 3 -> 'Fizz', multiples of 5 -> 'Buzz', both -> 'FizzBuzz', else the number as a string.
    """
    result = []
    for i in range(1, n+1):
        if i % 15 == 0:
            result.append('FizzBuzz')
        elif i % 3 == 0:
            result.append('Fizz')
        elif i % 5 == 0:
            result.append('Buzz')
        else:
            result.append(str(i))
    return result

if __name__ == "__main__":
    # Simple verification
    print(fb(15))