Ahnentafel Numbering System

Ahnentafel numbering begins with the starting individual, who is given a number of 1. From then on, an individual's father is assigned a number that is two times the number of the individual. The mother is assigned a number that is twice the individual's, plus 1.  If you are number one, your father is 2, your mother is 3, your father's father and mother are 4 and 5 and your mother's father and mother are 6 and 7 and so on. If a person is missing, their number is skipped. The child of any person always has a number that is one half the number of the father. So Ahnentafel numbers will be skipped for great-grandparents, etc. for who you have not entered information.

Because Ahnentafel number increase exponentially, they quickly become very large.  For example by the 20th generation, the Ahnentafel number in the direct male line would be 524,288 and by the 25th generation the Ahnentafel number in the direct male line would be 16,777,216.