K-Unique Sequence

A sequence of N integers is called K-unique if, when it is split into N/K subsequences of K contiguous elements, each subsequence consists of K distinct integers. For example, consider this sequence of 6 integers. (2, 10, 2, 8, 3, 6) This sequence is 2-unique, because when you split it into 3 subsequences each of 2 contiguous elements as below, (2, 10), (2, 8), (3, 6), each subsequence consis