MathDB
IMO Shortlist 2011, Number Theory 6

Source: IMO Shortlist 2011, Number Theory 6

July 11, 2012
algebrapolynomialnumber theoryIMO ShortlistDivisibility

Problem Statement

Let P(x)P(x) and Q(x)Q(x) be two polynomials with integer coefficients, such that no nonconstant polynomial with rational coefficients divides both P(x)P(x) and Q(x).Q(x). Suppose that for every positive integer nn the integers P(n)P(n) and Q(n)Q(n) are positive, and 2Q(n)12^{Q(n)}-1 divides 3P(n)1.3^{P(n)}-1. Prove that Q(x)Q(x) is a constant polynomial.
Proposed by Oleksiy Klurman, Ukraine