Complete the series 15, 13, 11, 14, 17, __

🧠 Explanation (Math):

Given: 15, 13, 11, 14, 17, __
Step 1: Differences show a 2-by-2 pattern: −2, −2, +3, +3, then −4, −4 …
Step 2: After 17 apply −4 ⇒ next term = 13
Final Answer: 13