i think this is the answer for n=-2/a+4
14, 15, 20 | 2
7, 15, 10 | 2
7, 15, 5 | 3
7, 5, 5 | 5
7, 1, 1 | 7
1, 1, 1
Answer: × 3 × 5 × 7 = 420
Hope it helped,
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