On the k-error Sequences of 2~n-Periodic Binary Sequences
F_2上2~n-周期序列的k-错误序列

In order to depict and study randomicity of sequences better, this correspondence gives the concept of k-error sequences of keystream, and for , the counting function, i.e., the number of k-error sequences of 2n-periodic binary sequence, and the expected value of the number of 1-error sequences of 2n-periodic binary sequences are provided.