John Derbyshire's "Prime Obsession" opens with "Like many other
performances, this one begins with a deck of cards." Pages 3 thru 7
follow.

3 4 5 6 7

Your post on the "harmonic mean" is marginally related to this story about
cards. I thought readers unfamiliar with this physical interpretation of
the "harmonic series" would enjoy it.

If you make one "minor" change to the harmonic series by raising
each term to the s power, where s is complex, you get the Riemann zeta
function. The formerly "divergent" series suddenly becomes the most
fascinating function ever imagined.