(2+1).(2^2+1).(2^4+1).(2^64+1)+1
=(2-1)(2+1).(2^2+1).(2^4+1).(2^64+1)+1
=(2^2-1)(2^2+1).(2^4+1).(2^64+1)+1
=(2^4-1)(2^4+1).(2^64+1)+1
=(2^8-1).(2^64+1)+1
.
=(2^64-1)(2^64+1)+1
=2^128-1 +1
=2^128
2^1的末尾數(shù)是：2
2^2的末尾數(shù)是：4
2^3的末尾數(shù)是：8
2^4的末尾數(shù)是：6
2^5的末尾數(shù)是：2
.
2^n的末尾數(shù)是關(guān)于2,4,8,6循環(huán)
128/4=32
所以2^128的末尾數(shù)是：6
即（2+1）（2^2+1）（2^4+1）.（2^64+1）+1的末尾數(shù)是：6