A Fibonacci Word is a specific sequence of binary digits (or symbols from any two-letter alphabet). The Fibonacci Word is formed by repeated concatenation in the same way that the Fibonacci numbers are formed by repeated addition.
Create a function that takes a number n as an argument and returns the first n elements of the Fibonacci Word sequence.
If n < 2, the function must return "invalid".
fibo_word(1) ➞ "invalid"
fibo_word(3) ➞ "b, a, ab"
fibo_word(7) ➞ "b, a, ab, aba, abaab, abaababa, abaababaabaab"
N/A