proof about product of 4 integers

samedi 28 juin 2014

1. The problem statement, all variables and given/known data

Prove that the product of four consecutive integers is always one less than a perfect square.

3. The attempt at a solution

I tried looking at the product [itex] (n-1)(n)(n+1)(n+2)=x^2-1 [/itex]

but i couldn't seem to get anything useful out of it. I added one to both sides .

I tried to see if i could some how show that the product of the four integers plus 1 had an odd number of divisors but I couldn't see a way to do it. I did notice that these numbers are never divisible by 2,3,or 4, and alot of the time they produce a prime, all though I didn't check very many.

And when it wasn't a prime it was divisible by 5. I was trying to think of a way to do this with Pythagorean triples but im not sure.





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