Abstract: Binary cyclic sequences have been widely used in the research on shared cont-rollers. The point is:that an usable sequence represents a usable scheme of the shared controller, However,to search for all the usable sequences,the old methods have to take all the primitive cyclic sequences as their basic sequences and remove unu-sable sequences from the basic ones.In fact,these basic sequences contain a large number of equivalent sequences and sub-cyclic sequences which are definitely unusable,and removal of these sequences will save considerable amount of calcu-lations.

Key words: shared controller, combinatorial coun-ting, binary cyclio sequence