Combinatorics with repetition after specific interval

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I have to choose $K$ values $N$ such that the $K$ values that are chosen can be repeated after $10$ other $k$ elements

I feel like you need to consider the order too because you need to keep track of repetition after $10$ elements

I know the formula for $N$ choose $K$ with repetition, how can I plug this $10$ in the formula to achieve the desired result.

n + k - 1Ck = (n+k-1)!/(k! (N-1)!)

or is it some other formula altogether?