Computer program for quasi-random stimulus sequences with equal transition frequencies

C language routines are presented for the generation of randomized stimulus sequences constructed from multiple presentations of m stimuli satisfying sequential constraints with respect to the frequencies of the occurrence of n-gram subsequences. Applications are suggested for sequential experiments in which main effects for the present stimulus and the stimuli in the preceding (n?1)-length substring can be tested, as well as the interactions among stimuli at the various positions in the substrings.