MathDB
Divisible

Source: 2013 China Mathematical Olympaid P5

January 14, 2013
modular arithmeticalgebrapolynomialfunctionnumber theory proposednumber theory

Problem Statement

For any positive integer nn and 0in0 \leqslant i \leqslant n, denote Cnic(n,i)(mod2)C_n^i \equiv c(n,i)\pmod{2}, where c(n,i){0,1}c(n,i) \in \left\{ {0,1} \right\}. Define f(n,q)=i=0nc(n,i)qif(n,q) = \sum\limits_{i = 0}^n {c(n,i){q^i}} where m,n,qm,n,q are positive integers and q+12αq + 1 \ne {2^\alpha } for any αN\alpha \in \mathbb N. Prove that if f(m,q)f(n,q)f(m,q)\left| {f(n,q)} \right., then f(m,r)f(n,r)f(m,r)\left| {f(n,r)} \right. for any positive integer rr.