java – help understanding the recurrence relation of an algorithm

I have the following code which I have to figure out the recurrence relation, but I am having a bit of a trouble understanding what the algorithm does exactly.

Interesting-Product(A(1..n))

if n = 1 then return

for i := 1 to n/3   do 
    A(i) = A(i)*A(i+(n/3))  
 
Interesting-Product(A(1..n/3))

 for j := (n/3) + 1 to   2n/3   do
      A(j) = A(j)*A(j+(n/3)) 

 Interesting-Product(A(1..n/3)) 

I’m taking an algorithms class and having trouble understanding the code.