Abstract: A computer-implemented sequence analysis process is provided for determining frequency in an n-gram hash sequence of a symbolic string, such as a series of characters. The method includes initializing a hash table, creating a matrix, reading the present value in the sequence, determining whether the present value is unknown, inserting a value index into the hash table if unknown and identifying the value index otherwise, and incrementing a cell within the array. The hash table has a plurality of levels from one to n. The matrix includes first and second indices corresponding to an array of cells. The first index corresponds to an end of a prior value, while the second index corresponds to a start of a present value. The cell corresponds to the first index for the prior value and the second index for the present value.