Exercise for the reader
More from Chalkdust

How much hair?
Thomas Sperling discusses some furry Fermi problems
Revisiting the 1986 computer classic Number Munchers!
Belgin gets hooked on a classic maths game...in 16 bits! Here's her review...
A Compendium of Mathematical Methods
We review the second of this year's nominees for the Book of the Year
In conversation with Clifford Cocks
We chat to the crypto chief about inventing RSA... but not being able to tell anyone
Five gold rings
And on the fifth day, some rather Algebraic Golden Rings:
Hunting for polydivisibles
The search for polydivisible numbers in different bases: how many can you find?
