This simple page will let you explore the sequence that is given by the following simple rule:

In math-ese, this translates into:

The rules above give very different sequences if we use different starting numbers. Try some of the following starting numbers:

Try it out!

  • Why does the computer stop when it gets to 1? What would the sequence be that starts at 1?
  • Can you predict how long the sequence will be if you know the starting number?
  • Will the sequence always reach 1? (This question is known in mathematically knowledgable cirlces as the Collatz Conjecture.)

  • Starting Number: