Killer Sudoku #68
In each cell of the NxN grid, enter a number in the range 1–N. Each number must appear exactly once in each row and column, and in each grey and white block (but not in each region with a given number).
Additional rules: The sum of the numbers in a region must equal the given number.
Short manual
Combinations tables give all the valid combinations for a given sum and number of digits. You can also use the calculator.
Enter the sum and number of digits in the fields below, and click the Calculate button.