A = zeros(3, 3, 3);
A(3^3+1) = 1;
Error is caused when you try to add an element to a matrix outside the original dimensions. Matlab automatically grows the array to make this happens, but in this case, it doesn't know which dimension to add your new value.
BUT, you shouldn't be growing arrays in the first place as it's a bad coding practice prone to slow codes. Essentially, Matlab has to copy your array to a new size and delete the previous array every time.