On relatively prime numbers and oil drops
Graheme L. Cohen · International Journal of Mathematical Education in Science and Technology · 1993
The probability that n positive integers, chosen at random, are relatively prime is 1 /ζ("), where ζ is Riemann's function. This is well known when n = 2, but not so well known otherwise. The proofs and associated discussion of the statement allow us to introduce many aspects of elementary number theory. Furthermore, there is an interesting application to Millikan's famous oil‐drop experiment.