theorem :: NUMBER09:26

{ ((2 |^ n) - 1) where n is Nat : ( (2 |^ n) - 1 <= 10 |^ 6 & (2 |^ n) - 1 is a_product_of_two_primes ) } = {((2 |^ 4) - 1),((2 |^ 9) - 1),((2 |^ 11) - 1)}