MathDB
5 - digit number - All-Russian MO 2004 Regional (R4) 8.7

Source:

September 27, 2024
number theoryDigits

Problem Statement

A set of five-digit numbers {N1,...,Nk}\{N_1,... ,N_k\} is such that any five-digit a number whose digits are all in ascending order is the same in at least one digit with at least one of the numbers N1N_1,...... ,NkN_k. Find the smallest possible value of kk.