Different sequences are reproduced or memorized with varying degrees of difficulty, depending on their structure. We obtained preliminary support for the hypothesis that difficulty of encoding is correlated with the perceived randomness of the sequence. Since the randomness of a sequence can be defined by its complexity, namely, the length of the shortest computer program for reproducing the sequence, we suggest that introducing randomness in terms of complexity may foster students' understanding. Subjective complexity, however, is maximal for sequences with exaggerated alternations, as is apparent-randomness. Thus, misperceptions of randomness cannot be corrected by the complexity approach. They can only be better understood.