  The generalized binary sequences of order 2 have been used to construct good
binary cyclic codes [4]. The linear complexity of these sequences has been
computed in [2]. The autocorrelation values of such sequences have been
determined in [1] and [3]. Some lower bounds of 2-adic complexity for such
sequences have been presented in [5] and [7]. In this paper we determine the
exact value of 2-adic complexity for such sequences. Particularly, we improve
the lower bounds presented in [5] and [7] and the condition for the 2-adic
complexity reaching the maximum value.
