Skip to main content
OlympiadHQ

Browse · MATH

Print

jmc

algebra intermediate

Problem

If is an integer, such that , for how many values of is equal to a positive integer?
Solution
We can re-write the product as The numerator of each fraction nicely cancels with the denominator of the next fraction, so the entire product telescopes, leaving just the fraction . For to be an integer, it follows that must be even and must be odd. The odd numbers from are given by ; there are such numbers.
Final answer
1004