As the title suggest. How many ways are there to fill up a $4 \times 4$ matrix with numbers $1$ to $16$, so that its rank is $1$ under modulo $17$ (i.e. consider elements of the matrix under $Z_{17}$)
Rank being 1 basically means all rows or columns are linearly dependent. If we look at a simple case, $2 \times 2$ matrix with numbers $1$ to $4$, under modulo $5$, all I can find is
\begin{matrix} 1 & 4\\ 3 & 2 \end{matrix}
and its rotations. But I am not sure how to generalize this to higher orders..
I wrote a python script to find them by brute force. The matrices all have $1$ in the first row and first column, and the entries in both the first row and first column are in increasing order (viewing them temporarily as elements of $\mathbb{Z}$.) I found $256$ such matrices. Of course, the rows and columns can each be permuted without changing the rank, so each matrix represents $24^2$ matrices.
I don't see any patterns at all. $256=16^2$ gives one hope, but for me, at least, it's an empty promise. Because of that, I'm appending a list of all $256$ matrices. Maybe you'll see something I don't.
In the listing below, the matrices have been flattened for typographical considerations, so the first line represents the matrix, $$\begin{bmatrix} 1 &2 &3 &6\\ 4 &8 &12 &7\\ 13 &9 &5 &10\\ 16 &15 &14 &11\end{bmatrix}$$