Ahnentafel numbering starts with a specified individual and lists his or her ancestors. Each individual is numbered according to the following pattern
1. The first individual is number 1.
2. The father's number is calculated by multiplying the child's number by 2.
3. The mother's number is calculated by multiplying the child's number by 2 and adding 1.
4. For example, the father of individual number 16 (who is the great-great-grandfather of individual number 1) is 32, and the mother is 33. An ahnentafel numbering system usually would only contain up to 32 generations because the numbering system becomes impractical. The number of an individual in the 32nd generation is in the billions.