This puzzle I created for 21st Indian Sudoku Mock Test.
"Prime Number Sudoku" Instructions:
Fill in the grid with digits from 1 to 9 so that each row, column and 3x3-box has exactly one of each digit. Morever greyed squares can only contain prime Numbes e.g. Greyed cells can contain only 2, 3, 5, 7 numbers.
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