11
12
17
15
Answer is Wrong!
Answer is Right!
The answer is $\boxed{\text{D}}$, 15.
The sequence is a combination of two arithmetic sequences: 1, 5, 9, 13, … and 5, 7, 9, 11, … The first sequence has a common difference of 4, and the second sequence has a common difference of 2. The terms in the sequence are alternately from the two sequences, starting with the first sequence. Therefore, the terms in the
288 448s170.8 0 213.4-11.5c23.5-6.3 42-24.2 48.3-47.8 11.4-42.9 11.4-132.3 11.4-132.3s0-89.4-11.4-132.3zm-317.5 213.5V175.2l142.7 81.2-142.7 81.2z"/> Subscribe on YouTube