# Name the matrix (not the game show)

I have a matrix of the following form:

$\begin{matrix} a_1 & 0 & \ldots & 0 \\ a_2 & a_1 & \ldots & 0 \\ \vdots & \vdots & \ddots & \vdots \\ a_n & a_{n-1} & \ldots & a_1 \end{matrix}$

I'd like to know if this matrix has a special name (or even if it's a sum/product of special matrices). The thing is, I need to build this matrix in matlab, and I could use some for loops, but I'd rather use some clean builtin functions.

Thanks

Edit: I just had a thought, maybe it can be a Vandermonde matrix times some other (unknown) matrix to nullify the terms above the diagonal...

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Funny, I was looking for the name Vandermonde matrix and thought of Toeplitz... –  Tobias Kienzler Nov 13 '14 at 22:21