The series alternates between two interleaved patterns at odd and even positions. Odd positions (1st, 3rd, 5th): 8, 14, 11, 14, 18 follow add 6, subtract 3, add 3, add 4. Even positions (2nd, 4th, 6th, 8th, 10th): 2, 6, ?, 6, 2 form a symmetric pattern. Position 6 must be 9 to balance the sequence symmetrically around positions 4 and 8 (both 6).