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Matrix elements

A=[1214362181012194023361]A=\left[\begin{array}{rr}12 & 14 & -3 & 6 \\2 & 18 & -10 &12 \\1 &-9 &40 & -2 \\3 &3 &6 & 1\end{array}\right]
A2,4=A_{2,4}=