The ancestry report uses 'Ahnentafel' numbering. This means that a person's parent's numbers will be twice as large as the person's number. So if someone's number is 15, her father will be number 30, and mother will be 31. Her child will be number 7.
This web site produced 19 Apr 2000 by Personal Ancestral File, a product of
The Church of Jesus Christ of Latter-day Saints.