Dismiss Notice
Join Physics Forums Today!
The friendliest, high quality science and math community on the planet! Everyone who loves science is here!

5th puzzle post-the impossible sequence

  1. Feb 21, 2006 #1
    :cool:


    o.k wats missing from the LINE UP....

    9,36,225,256,400, _ ,1225,1600 .

    damm, u got all the others instantly.. hope it isnt the case for this ...its a 3 step solution ...sorta ,nothing too ridiculous ,,and its slightly lateral and mensa ' ry.
    goood luck
    btw who ever solves it post as clearer method as possible
     
    Last edited: Feb 21, 2006
  2. jcsd
  3. Feb 21, 2006 #2
    Well, I found a pattern, though if this is the one you’re looking for is anyone’s guess.
    Take the pattern, 3, 3, 5, 4, 4, 6, 5, 5, 7,…..
    Multiply it term by term with the pattern 1, 2, 3, 4, 5, 6, 7, 8
    Square each one, then the pattern is
    (3x1)^2 = 9
    (3x2)^2 = 36
    (5x3)^2 = 225
    (4x4)^2 = 256
    (4x5)^2 = 400
    (6x6)^2 = 1296
    (5x7)^2 = 1225
    (5x8)^2 = 1600
    So the answer is 1296
     
  4. Feb 21, 2006 #3
    yep dav yep but wat r the origins of those numbers on the left ...the ones on the far left......
    btw how do u make ur writting invisible i dunno how to do that
     
    Last edited: Feb 21, 2006
  5. Feb 21, 2006 #4
    I'm not sure if you're looking for something else that's significant about the series 3,3,5,4,4,6,5,5,7,6,6,8,7,7,9... But essentially daveb's answer was:

    F1(n) = F1(n-1)+1*(n%3)*((n-1)%3)-.5*((n-1)%3)*((n-2)%3)
    F1(0) = 3

    (A complicated way of getting +0, +2, -1, +0, +2, -1, +0, +2, -1, etc.)

    F(n) = ((F1(n-1)+1*(n%3)*((n-1)%3)-.5*((n-1)%3)*((n-2)%3)) * (n+1))^2

    As for the invisible writing, it's pretty simple-- You enter:

    Now you see me

    Which becomes:

    Now you don't!

    DaveE
     
    Last edited: Feb 21, 2006
  6. Feb 22, 2006 #5
    acttually i was just going for the fact that each number represeted the amount of letters in the numbers from ...1 to 8 ...which makes it (3x6)^2 = 324
     
Share this great discussion with others via Reddit, Google+, Twitter, or Facebook




Loading...
Similar Threads for puzzle post impossible Date
Are Physicists better math puzzle solvers than mathematicans? Dec 24, 2017
4th puzzle post Feb 19, 2006
3rd puzzle post Feb 17, 2006
My 2nd puzzle post -sequence Nov 16, 2005
My 1st puzzle post Nov 16, 2005