Let us pair the squares of the numbers 1 to n with the squares of the numbers n+1 to 2n such that each pair sums up to a prime.

1. Demonstrate that it is not possible for n1=3, n2=?(find out) and n3=??(find out)
2. For what value of n there are exactly 2 ways to perform the task?

Hint: all answers are below 15