Since we have only even numbers multiplied and then we add a 1, we should get odd number. Shouldn't the smallest prime factor be between 2 nd 10? The answers are:

a) between 2 and 10

b)between 10 and 20

c)between 20 and 30

d)between 30 and 40

e)over 40

I was thinking that if it is the SMALLEST PRIME FACTOR it will be a 2 or 3 or 5 or 7....