Definition of a certain matrix I remember I came across matrix of the form 
$$\begin{bmatrix}
1 & 0 & 0 & 0\\
1 & 1 & 0 & 0\\
0 & 1 & 1 & 0\\
0 & 0 & 1 & 1\\
\end{bmatrix}$$
There is a name for it but I can't remember. Does anyone know the name of the matrix of this form?

It is called the Jordan Block .
$$\left(\begin{matrix}
\lambda & 1 & 0 & \cdots & 0 \\
0 & \lambda & 1  & \cdots & 0 \\
\vdots & \vdots & \vdots & \ddots & \vdots\\
0 & 0 & 0 & \lambda & 1\\
0 & 0 &  0 & 0 & \lambda
\end{matrix}\right)$$
