1
Input: 2 → [?] → 1, what is the rule? =
2
Input: 1 → [×3 - 2] → ? =
3
Input: 5 → [?] → 7, what is the rule? =
4
Input: 4 → [?] → 6, what is the rule? =
6
Input: 6 → [?] → 18, what is the rule? =
7
Input: 5 → [?] → 10, what is the rule? =
8
Input: 8 → [?] → 17, what is the rule? =