At least two sets of numbers add up to get one.

So if an is an even number,

N > = 2+an/2 (put the ones that can make up an together and divide them into n groups. If there are two more, there must be two groups).

Similarly, when an is odd, it is 2+(an+ 1)/2.

When an=2007

n÷= 1006

If an is not equal to 2007, then the calculated n is less than 1006, right?

The an given in the title is an indefinite value, that is, all the values of an must be met, so 1006 can just meet all the values of an, and if it is smaller, an=2007 will not be met.

So the minimum value of n is 1006.