MathDB
p^2|binomial sum of p choose k, k<2p/3

Source: VJIMC 2001 1.2

July 23, 2021
number theorySummationbinomial coefficients

Problem Statement

Prove that for any prime p5p\ge5, the number 0<k<2p3(pk)\sum_{0<k<\frac{2p}3}\binom pkis divisible by p2p^2.