Number of length n+6+2 0..6 arrays with every value 0..6 appearing at least once in every consecutive 6+3 elements, and new values 0..6 introduced in order.

A242321

Number of length n+6+2 0..6 arrays with every value 0..6 appearing at least once in every consecutive 6+3 elements, and new values 0..6 introduced in order.