MathDB
lcm(1,2,...,n)

Source: Romania TST 1995

September 28, 2009
number theory unsolvednumber theory

Problem Statement

For each positive integer n n,define f(n)\equal{}lcm(1,2,...,n). (a)Prove that for every k k there exist k k consecutive positive integers on which f f is constant. (b)Find the maximum possible cardinality of a set of consecutive positive integers on which f f is strictly increasing and find all sets for which this maximum is attained.