I like to use computers to play with fun math problems. This page has notes on some of my projects, for those very few who may be interested. (And so I can remember them.)

If you have any fresh insight into any of these puzzles, I’d love to hear about it! You can reach me at chaffin (at) gmail (dot) com.

Hardware

• Building a Skylake system
• A smarter thermostat – turning the heat on at the right time

OEIS sequences

The Online Encylopedia of Integer Sequences is an endless source of fun projects.

• Van Eck’s sequence (A181391)
• Multiplicative persistence (A003001)
• Zeros in powers of 2 (A006889)
• Matchstick squares (A294249)
• Repunit primes (A004023)

Other games & puzzles

• Coin-sliding puzzles by Erik Demaine
• Magic square of squares

Coming eventually

• The Recaman Sequence
• Paterson’s Worms
• Gathering for Gardner exchange gifts
• Superpermutations
• No-three-in-line problem
• A 7-piece vanishing-square puzzle
• Weiferich primes
• Hofstadter Q sequence