The Collatz conjecture is an unsolved conjecture in mathematics. It is named after Lothar Collatz, who first proposed it in 1937. The conjecture is also known as the 3n + 1 conjecture, as the Ulam ...

Experienced mathematicians warn up-and-comers to stay away from the Collatz conjecture. It’s a siren song, they say: Fall under its trance and you may never do meaningful work again. The Collatz ...

Seaweed? Worms? Bad hair day? The animation below is a new way to look at the Collatz conjecture, one of the most high-profile open problems in mathematics. The conjecture is easy to explain, given ...

Some years ago, I wrote here about “hailstone numbers” (Follow that hailstone, 8 April 2016). These are numbers that are generated when you try your hand at the Collatz Conjecture—sometimes described ...