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3 becomes 10 becomes 5 becomes 16

  1. Aug 29, 2008 #1
    Hi,I have one question for you guys because I try but didn't quite work.Last week one of professor asked me a question . he asked me this.

    Think of a number (a positive integer), If it's odd, muliply by three and add one. If it's even, divide by two. Repeat this proces.

    like this one : 3 becomes 10 becomes 5 becomes 16 becomes 8 becomes 25 becomes .........etc

    Do you always reach 1 at some point Or are there any numbers which never reach 1?

    And finally I try to find this idea in the internet but I didn't get what trying to say.
  2. jcsd
  3. Aug 29, 2008 #2


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    Science Advisor

    Re: unsolved

    that's the "Collatz conjecture". If you find a proof, don't tell your professor, he will only publish it as his own and become famous- send it to me instead!
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