MathDB
Putnam 1953 B2

Source: Putnam 1953

July 16, 2022
PutnamIntegerpolynomial

Problem Statement

Let a0,a1,,ana_0 ,a_1 , \ldots, a_n be real numbers and let f(x)=anxn++a1x+a0.f(x) =a_n x^n +\ldots +a_1 x +a_0. Suppose that f(i)f(i) is an integer for all i.i. Prove that n!akn! \cdot a_k is an integer for each k.k.