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问题: 计算3*5*17.....(2的2N-1次方+1)

等于多少

解答:

3*5*17.....(2的2N-1次方+1)
=(2+1)(2^2+1)(2^4+1)……{2^[2^(n-1)]+1}
=1*(2+1)(2^2+1)(2^4+1)……{2^[2^(n-1)]+1}
=(2-1)(2+1)(2^2+1)(2^4+1)……{2^[2^(n-1)]+1}
=(2^2-1)(2^4+1)……{2^[2^(n-1)]+1}
=(2^4-1)(2^4+1)……{2^[2^(n-1)]+1}
={2^[2^(n-1)]-1}{2^[2^(n-1)]+1}
=2^(2^n)-1