// 易错点6：返回整个数组（如this.res）→ 不符合题目要求，题目要求返回单个数值
* 序列: 1, 5, 19, 41, 109, ...
。旺商聊官方下载对此有专业解读
Don't feel down if you didn't manage to guess it this time. There will be new sports Connections for you to stretch your brain with tomorrow, and we'll be back again to guide you with more helpful hints.
MIT — Rikkert ten Klooster