Living for nine generations: father, ancestor, Zeng, Gao, Tian, Lie, Tai, Yuan, Nose. The next nine generations: son, grandson, Zeng, Xuan, Lai, Xuan, Chen, Yun and Er. Or: son, grandson, great grandson, great grandson, great grandson, great grandson, great grandson, great grandson, great grandson, great grandson, great grandson, great grandson, great grandson, great grandson, great grandson, great grandson, great grandson, great grandson, great grandson, great grandson, great grandson, great grandson, great grandson, great grandson, great grandson, great grandson, great grandson, great grandson.
The ancestors of the 18th generation, as the name implies, are the first nine generations and the next nine generations. All of them are in the 18th generation. One thing we should pay attention to here is ourselves, referred to as "I" for short. "I" is the watershed between the first nine generations and the next nine generations, not included in the "Eighteen Ancestors"