The ancestry report uses 'Ahnentafel' numbering. This means that the numbers for a person's parents will be twice as large as that person's number. For example, if a woman's number is 15, her father will be number 30, and her mother will be 31. Her child will be number 7.
This web site produced 30 Mar 2015 by Personal Ancestral File, a product of
The Church of Jesus Christ of Latter-day Saints.