MathDB
A 58

Source:

May 25, 2007
Divisibility Theory

Problem Statement

Let k14k\ge 14 be an integer, and let pkp_k be the largest prime number which is strictly less than kk. You may assume that pk3k4p_k\ge \tfrac{3k}{4}. Let nn be a composite integer. Prove that [*] if n=2pkn=2p_k, then nn does not divide (nk)!(n-k)!, [*] if n>2pkn>2p_k, then nn divides (nk)!(n-k)!.