2^48-1
=(2^24+1)(2^24-1)
=(2^24+1)(2^12+1)(2^12-1)
=(2^24+1)(2^12+1)(2^6+1)(2^6-1)
2^6+1=65
2^6-1=63
所以2的48次方-1能被60-70间的两个整数整除.