9.7

Part of 1999 All-Russian Olympiad Regional Round

Problems(1)

n=a-b, no of prime factors - All-Russian MO 1999 Regional (R4) 9.7

Source:

Prove that every natural number is the difference of two natural numbers that have the same number of prime factors. (Each prime divisor is counted once, for example, the number

12

has two prime factors:

2

3

number theoryDivisors