I have problem with the following code

How to correct it?Code:Table[If[Mod[i, 3] <= 1 Or Mod[j, 3] <= 1, 29/512, 23/256], {i, 0, 3}, {j, 0, 3}]

By the way, I need to simplify

by Mathematica to get the output $\displaystyle -8.223178212$.Code:-9+\frac{69 (69)^{1/4}}{256}

Thanks.