Medium
__aba__ba_ab (find the correct letters to fill the blanks)
Explanation
Explanation
The complete sequence is simply the alternating pattern a,b,a,b,a,b,... repeated. Filling in the blanks according to their odd/even position (odd=a, even=b) gives 'abbab'.
PRO TIP
Re-check your working by substituting the answer back into the original question.