MathDB

2

Part of 2001 APMO

Problems(1)

Set of integers

Source: APMO 2001

3/19/2006
Find the largest positive integer NN so that the number of integers in the set {1,2,…,N}\{1,2,\dots,N\} which are divisible by 3 is equal to the number of integers which are divisible by 5 or 7 (or both).
number theorycountingfloor function