Dear Mr. Follin,
Thank you for posting your request on History Hub!
The Federal Government does not ordinarily create or maintain birth, death, marriage or divorce records. Such records are made and kept by State and local governments rather than the National Archives. We suggest that you review NARA’s website for how to Start Your Genealogy Research and Census Resources for tips on how to access census records that may be digitized in the National Archives Catalog or available on the websites of NARA’s partners. From 1790 to 1840, only the head of household is listed by name; other household members are merely counted in selected age groups.
We searched Ancestry and located All 1790 Census Results for Adam Sine; All Birth, Marriage & Death Results for Adam Sine; All Birth, Baptism & Christening Results for Jacob Sine; and All Birth, Baptism & Christening Results for Absalom Sine. There may be a fee for using Ancestry to access digitized records. However, you may view these records online at one of NARA's facilities for free via a NARA PC. For the nearest NARA location, please consult our web page at https://www.archives.gov/locations/.
You may wish to use Family Search for Free Family History and Genealogy Records; and FamilySearch Wiki to begin your research using information known about Adam Sine. Moreover, if you know where he lived and died, then you may be able to obtain property records or a Deed of Will from the state and/or county that may contain the names of his children.
We hope this is helpful. Best of luck with your research!