Ken's Puzzle of the Week

Talisman Squares

Place the numbers 1-16 into a 4x4 grid such that the difference between a number and any of its neighbors (including diagonally) is not less than 3.  In how many ways can this be done?  (Disregard rotations, reflections, and replacement with 17-x.)

Source: Original, based on several sources (formerly titled "Largest Difference Square".)

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