The first household record for Piteå rural parish covers 1720 to 1749. There are seven pages for Blåsmark, with seven numbered households, plus one page of soldiers' wives and their children.
The first household is headed by a Nils Larssson. There is a wife Margareta and six sons: Olof, Anders, Lars, Nils, Samuel and Per.
This may make sense if all their daughters died in infancy
There are ages for the people: Nils Larssson (53), wife Margareta (47) and six sons: Olof (21), Anders (18), Lars (17), Nils (12), Samuel (11) and Per (4).
These are not necessarily for 1720, nor necessarily all at the same time - although the age steps do make sense. Your Samuel would have been 11 in 1715 - so was the book started earlier than stated? It may well be, the dating seems to be an estimate by later archivists. Or is this another family after all?
There is also a year for each person, which does not seem to be the birth year: Nils Larssson (53) -1697, wife Margareta (47) - 1702 and six sons: Olof (21) - 1727, Anders (18) - 1730 and 1744, Lars (17) - 1726, 1744, adm 1747, Nils (12) - 1736, Samuel (11) - 1734 and Per (4) - 1745.
Piteå landsförsamling AI:1 (1720-1749) Bild 126 / sid 244 (AID: v138568.b126.s244, NAD: SE/HLA/1010154) http://www.arkivdigital.se/aid/info/v138568.b126.s244