Put the integers 1, 2, 3, … n in any order and call them a1, a2, a3, … an. Then form the product
P = (a1 – 1) × (a2 – 2) × (a3 – 3) … × (an – n).
Now: If n is odd, prove that P is even.
Put the integers 1, 2, 3, … n in any order and call them a1, a2, a3, … an. Then form the product
P = (a1 – 1) × (a2 – 2) × (a3 – 3) … × (an – n).
Now: If n is odd, prove that P is even.