2016 JBMO Problems/Problem 3

Revision as of 01:05, 23 April 2018 by Leonariso (talk | contribs) (Solution)

Problem

Find all triplets of integers $(a,b,c)$ such that the number

\[N = \frac{(a-b)(b-c)(c-a)}{2} + 2\]

is a power of $2016$.

(A power of $2016$ is an integer of form $2016^n$,where $n$ is a non-negative integer.)

Solution

It is given that $a,b,c \in \mathbb{Z}$

Let $(a-b) = -x$ and $(b-c)=-y)$ then $(c-a) = x+y$ and $x,y \in \mathbb{Z}$

We can then distinguish between two cases:

Case 1: If $n=0$


Case 2: If $n>0$

See also

2016 JBMO (ProblemsResources)
Preceded by
Problem 2
Followed by
Problem 4
1 2 3 4
All JBMO Problems and Solutions