MathDB
Actually, estimating the size of A is harder than the problem

Source: 2023 KMO P3

November 4, 2023
algebrapolynomial

Problem Statement

For a given positive integer n(2)n(\ge 2), find maximum positive integer AA such that there exists PZ[x]P \in \mathbb{Z}[x] with degree nn that satisfies the following two conditions.
[*] For any 1kA1 \le k \le A, it satisfies that AP(k)A \mid P(k), and [*] P(0)=0P(0)= 0 and the coefficient of the first term of PP is 11, which means that P(x)P(x) is in the following form where c2,c3,,cnc_2, c_3, \cdots, c_n are all integers and cn0c_n \neq 0. P(x)=cnxn+cn1xn1++c2x2+xP(x) = c_nx^n + c_{n-1}x^{n-1}+\dots+c_2x^2+x