ex.4-inima,coroana,stea,promit!!!!!

n = 3¹⁹ - 3¹⁷ + 3¹⁶
n = 3¹⁶ ( 3³ - 3 + 1)
n = (3⁸)² * 25 = (3⁸)² * 5² = (3⁸ * 5)² -> p.p.