1
Input: 3 → [?] → 13, what is the rule? =
2
Input: 3 → [?] → 14, what is the rule? =
4
Input: 9 → [?] → 6, what is the rule? =
6
Input: 4 → [?] → 20, what is the rule? =
7
Input: 8 → [?] → 7, what is the rule? =
8
Input: 10 → [?] → 28, what is the rule? =