A = (1 - 3)(3 + 1)(3² + 1)(3⁴ + 1)...(3¹⁶ + 1)
= -(3 - 1)(3 + 1)(3² + 1)(3⁴ + 1)(3⁸ + 1)(3¹⁶ + 1)
= -(3² - 1)(3² + 1)(3⁴ + 1)(3⁸ + 1)(3¹⁶ + 1)
= -(3⁴ - 1)(3⁴ + 1)(3⁸ + 1)(3¹⁶ + 1)
= -(3⁸ - 1)(3⁸ + 1)(3¹⁶ + 1)
= -(3¹⁶ - 1)(3¹⁶ + 1)
= -(3³² - 1)
= 1 - 3³²