2
Input: 2 → [?] → 12, what is the rule? =
3
Input: 1 → [?] → 5, what is the rule? =
4
Input: 3 → [?] → 15, what is the rule? =
5
Input: 1 → [?] → 11, what is the rule? =
6
Input: 2 → [?] → 4, what is the rule? =
7
Input: 1 → [?] → 0, what is the rule? =