The Semi-Magic Nine
Fill a 3×3 grid with the numbers 1 through 9, each used exactly once, so that all three rows and all three columns sum to 15. The diagonals are not required to sum to anything. Rotations and reflections count as different fillings. How many fillings are there? Give an integer.
Related problems & prerequisites
Worth solving first
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- Eight Claims About the Tally 5.0/10
Source: Variation on the 3×3 magic square, relaxing the diagonal condition; counting formulation written for AxiomIQ.