Challenge #3

Posted on April 22, 2006 by Brent

It’s been a little while since my last post… I plead spring break vacation. At any rate, hopefully you figured out that the last post was intended as an April Fool’s joke. I hope you didn’t embarass yourself too badly trying to guess random numbers. (=

Here are some number sequences. Can you figure out the pattern and give the next three terms for each? (Each sequence follows a different pattern.)

  1. 1, 3, 7, 15, 31, \dots
  2. 2, 5, 14, 41, 122, \dots
  3. 2, 6, 12, 20, 30, \dots
  4. 349, 32, 10, 2, 4, \dots

About Brent

Associate Professor of Computer Science at Hendrix College. Functional programmer, mathematician, teacher, pianist, follower of Jesus.
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2 Responses to Challenge #3

  1. Loweeel says:
    April 22, 2006 at 8:47 pm

    note: square brackets indicate positions/subscripts.

    1. 63, 127, 255. Pattern: [n+1] = 2n+1
    2. 365, 1094, 3281. Pattern: [n+1] = 3n-1
    3. 42, 56, 72. Pattern: [n+1] = n+([order in sequence of # n+1]*2)
    4. Don’t want to try 😀

  2. Laura says:
    April 24, 2006 at 9:04 am

    4. Add the digits together and double the result. So 8, 16, 14.

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