Can understand where p1+1 ,p2+1 and p3+1 came from?

#1

Can understand where p1+1 ,p2+1 and p3+1 came from? Can u explain?

#2

hi @riagoel3999 that is basically the power of each divisor,
say 2 is 3 times then p is 3 and u have 4 (p+1) options to take 2 in making a divisor of that no 0,1,2,3 times