Since Julia (ordinary) arrays have 1-based indices and are in column-major order, the linear index `k` and the Cartesian index `(i,j)` of an element in a `m×n` Julia array are related by: `k = i + m*(j - 1)`. The examples of conversion between linear and Cartesian indices in the doc. use incorrect formulae although the results were correct in the specific element at `(1,3)`. This can be easily checked for other indices than `(1,3)` with a simple `2×3` array (as in the examples) built by `A = reshape(collect(1:6),2,3)`.