Method of generating an efficient sequence of multi-level random numbers used for an information recording medium

A computer program that causes a computer to generate an efficient sequence of “nm+m−1” n-level random numbers, each sub-sequence of “m” successive random numbers thereof having a different pattern, comprising the steps of:

• generating a sequence of n-level random numbers based on an initial value, a number being generated at a time;
• determining whether a pattern of a subsequence of “m” successive random numbers including the newly generated number and “m−1” preceding numbers in an order of the generation thereof is “used”;
• if said pattern of said sub-sequence is “used”, setting a different value to said initial value;
• if said pattern of said sub-sequence is not “used”, accepting the newly generated number and marking said pattern as “used”;
• and
• wherein all of the steps are repeated until all of “nm” patterns of said sub-sequences of “m” successive random numbers are exhausted.