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Predict next Number

  1. Jul 8, 2013 #1
    Can you find the next number in a sequence

    0
    3
    18
    1
    1
    13
    8
    12
    21
    5
    4
    5
    38
    4
    14
    5
    5
    1
    6
     
  2. jcsd
  3. Jul 8, 2013 #2
    Anything could be generating that sequence. The logistic map, for example. That's the nature of chaos theory.
     
  4. Jul 8, 2013 #3
    Reading about the chaos theory its seem just that so I wonder if this group of numbers is any better

    2997
    3003
    3039
    3041
    3043
    3069
    3085
    3109
    3151
    3161
    3169
    3179
    3255
    3263
    3291
    3301
    3311
    3313
    3325
    3331
     
  5. Jul 9, 2013 #4

    micromass

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    Like already been said, it can be anything. You should be given a rule to predict the next number, otherwise it is very arbitrary.

    Questions like "find the next number", like you see on IQ-tests, are not part of mathematics. It's more pattern recognition than anything.

    So, can you give us some information where this came from?
     
  6. Jul 9, 2013 #5

    jbunniii

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    What number comes next in this sequence?

    3, 1, 4, 1, 5, ...

    If you said 9 then you might be mathematically inclined. If you said 1 then go back to your crossword puzzle or your "Bad Girls Club" tv show. If you said some other number then you're just being a contrarian clown, but at least you didn't say 1.
     
  7. Jul 9, 2013 #6
    I thank you for your answers, but I think I would only be wasting your time with any more question. I think you are right I will not find anything
     
  8. Jul 9, 2013 #7

    micromass

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    Maybe we will find something. But we need to know first how you got these numbers.
     
  9. Jul 9, 2013 #8
    That's judgemental.

    x_n = [1+(-1)^n]/2 + [1-(-1)^n](n+5)/4

    y_n = floor( pi*10^(n-1) )
    z_n = 10[ y_n/10 - floor(y_n/10) ]

    To me, x is a mathematically nicer sequence than z.
     
  10. Jul 10, 2013 #9
    Hello,

    I have found the next number to be [itex]6[/itex]. I ran these numbers through a program i made which detects patterns.
     
  11. Jul 10, 2013 #10

    HallsofIvy

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    When I was in college, one teacher gave us the sequence 18, 17, 16, 15, 14 and challenged us to find the next number in the sequence. The correct answer? 22. Those are the numbers of the subway stops on his way to work. At station number 14, the train shifts to a different line.

    Another popular sequence is this: Draw a circle and mark n points around the circumference of the circle- NOT equally spaced so that the lines drawn from each point to each other divide the circle into the largest possible number of areas. How many areas will that be for each n?

    Whe n= 1 there is no line so only one area: a(1)= 1. When a= 2, there is one line so two areas: a(2)= 2. When n= 3, the lines form a triangle so there are the three areas outside the triangle and the area inside the triangle: a(3)= 4. When there are four points, the lines form a quadrilateral with the two diagonals- four areas inside the quadrilateral, four areas outside: a(4)= 8. When there are five points, there will be 16 areas. How many areas will there be with 5 points?

    Answer: 31.

    There is, in fact, a simple formula for this one: with n points, there are [tex]\begin{pmatrix}5 \\ 0 \end{pmatrix}+ \begin{pmatrix}n \\ 1\end{pmatrix}+ \begin{pmatrix}n \\ 2 \end{pmatrix}+ \begin{pmatrix}n \\ 3\end{pmatrix}+ \begin{pmatrix}n \\ 4\end{pmatrix}+ \begin{pmatrix}n \\ 5\end{pmatrix}[/tex] areas.
     
  12. Jul 10, 2013 #11

    jbunniii

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    You should try it with the stock market!
     
  13. Jul 10, 2013 #12
    It isn't a number. This sequence is obviously generated by the sequence given by
    $$a_n=\left\{\begin{matrix}0, & n=1 \\ 3, & n=2 \\ 18, & n=3 \\ 1, & n\in\{4,5,18\} \\ 13, & n=6 \\ 8, & n=7 \\ 12, & n=8 \\ 21, & n=9 \\ 5, & n\in\{10,12,16,17\} \\ 4, & n\in\{11,14\} \\ 38, & n=13 \\ 14, & n=15 \\ 6, & n=1 \\ \left\{\text{PhysicsForums is awesome}\right\}, & n\geq 20\end{matrix}\right.$$

    This looks ridiculous, but there's a point to this. There isn't an actual way to predict the next number without knowing a rule by which the numbers are picked.
     
    Last edited: Jul 10, 2013
  14. Jul 11, 2013 #13
    A while ago someone posted something similar about numbers in the Qur'an. This looks similar.
     
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