Ta có :
B = 2.4 ( 3² + 1 ) (3⁴ + 1) (3⁸+ 1) ( 3¹⁶ + 1)
=>B=( 3 - 1 ) ( 3 + 1 ) ( 3² + 1 ) ( 3⁴ + 1 ) ( 3⁸+ 1 ) ( 3¹⁶ + 1 )
Áp dụng: A2-B2=( A + B ) ( A - B )
=>B=( 3² - 1 ) ( 3² + 1 ) ( 3⁴ + 1 ) ( 3⁸ + 1 ) ( 3¹⁶ + 1 )
=>B=( 3⁴ - 1 ) ( 3⁴ + 1 ) ( 3⁸ + 1 ) ( 3¹⁶ + 1 )
=>B=( 3⁸ - 1 ) ( 3⁸ + 1 ) ( 3¹⁶ + 1 )
=>B=( 3¹⁶ - 1 ) ( 3¹⁶ + 1 )
=>B= 332 - 1
Mà A=3³² - 1
=> A=B=3³² - 1