MathDB
Polynomial involving sum of digits

Source: Turkey Olympic Revenge 2023 P3

March 6, 2023
number theoryolympic revengePolynomialssum of digits

Problem Statement

Find all polynomials PP with integer coefficients such that s(x)=s(y)    s(P(x))=s(P(y)).s(x)=s(y) \implies s(|P(x)|)=s(|P(y)|). for all x,yNx,y\in \mathbb{N}. Note: s(x)s(x) denotes the sum of digits of xx.
Proposed by Şevket Onur YILMAZ