Determin4nts

Now we are at the 4 by 4 matrix.

Find

$det\left( \begin{array}{ccc}1 & 1 & 1 & 1 \\1 & 2 & 3 & 4 \\ 1 & 3 & 6 & 10 \\ 1 & 4 & 10 & 20 \end{array} \right)$

Wolfy is allowed, but try and find out how its calculated by yourself...

and guessing is applicable in this case.