Could this bof interest? Per and Peder could well be the same person, not unusual changing.
In local history book for Nittedal I have found: Farm Nedre Lower) Slattum, cotter's farm Saga (saw). Smallholder, the son from MARKERUD farm Per Embretsen b.1726 died 1788, married with Marte Andersdater Slattumeiet. Children Nils, Embret and Marte.
Markerud farm: User Embret Persen born ab. 1677 died 1736, married with Lisbet Hansdatter died 1742. Among other children they have the son Per b. 1726.
The age given when Peder Embretsen died cannot be right. Since the local history book says he was born 1726, I believe you find him on the left page where it reads: "Marie besøgelsesdag wed Nittedahlen, Engebret Marcheruds Barn, Peder. (Festum Visitatio Mariæ = July 2.)