MathDB
Number of cool polynomials is even

Source: 2024 Israel TST Test 1 P3

August 29, 2023
algebrapolynomialnumber theorymodular arithmeticprime numbers

Problem Statement

Let nn be a positive integer and pp be a prime number of the form 8k+58k+5. A polynomial QQ of degree at most 20232023 and nonnegative integer coefficients less than or equal to nn will be called "cool" if pQ(2)Q(3)Q(p2)1.p\mid Q(2)\cdot Q(3) \cdot \ldots \cdot Q(p-2)-1. Prove that the number of cool polynomials is even.