Task 2.

In a table consisting of $n$ rows and $m$ columns, numbers (not necessarily integers) were written such that the sum of the elements in each row is 408, and the sum of the elements in each column is 340. After that, $k$ columns were added to the table, the sum of the elements in each of which is 476, and a column, the sum of the elements in which is 272. The resulting table has a sum of elements in each row equal to 544. Find the numbers $n, m$, and $k$ for which the expression $2n - 3m + 6k$ takes the smallest possible natural value. For the found parameters $n, m$, and $k$, provide an example of the specified table.
Answer: 4 when $n=65, m=78, k=18$.