[split] recurring word sequences

[doranchak]

I am very curious about the general case of sequences of n "vords".

For example, instead of considering only patterns of the type XYXY, consider any sequence ABCD.  In other words, consider every combination of 4 vords.

For each combination, compute the expected number of occurrences based on your probability calculations.  Then compare to the actual count, and sort the list of combinations in descending order of the difference between actual and expected.  Which combinations are unusually repetitive (or unusually non-repetitive, i.e. phobic of specific combinations) and are thus statistically significant compared to random distributions of vords?  

I suspect this test might have already been performed - perhaps someone can point me to existing research on this.