Rank of a special matrix

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If a specific $n$ by $n$ matrix A satisfies the relation that $$A^n=0$$

What information can we get about its rank?

Update: Certainly it is not full rank, but can we dig more out of it?

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aCTOH's brief comment gives the answer without getting into how. Here is a description.

Take the $n\times n$ identity matrix. Now remove its last column and as replacement put the zero vector, but as the first column. Call this matrix $A_1$.

For any $k<n$ remove the last $k$ columns from $I_n$ and replace them by equal number of zero vectors, but at the front. Call this matrix $A_k$

Note that for all these matrices the rank is the number of non-zero columns, and compute the powers for all these matrices.