# Predict next Number

1. Jul 8, 2013

### msticky

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. Jul 8, 2013

### Goa'uld

Anything could be generating that sequence. The logistic map, for example. That's the nature of chaos theory.

3. Jul 8, 2013

### msticky

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

4. Jul 9, 2013

### micromass

Staff Emeritus
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?

5. Jul 9, 2013

### jbunniii

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.

6. Jul 9, 2013

### msticky

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

7. Jul 9, 2013

### micromass

Staff Emeritus
Maybe we will find something. But we need to know first how you got these numbers.

8. Jul 9, 2013

### economicsnerd

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.

9. Jul 10, 2013

### oneplusone

Hello,

I have found the next number to be $6$. I ran these numbers through a program i made which detects patterns.

10. Jul 10, 2013

### HallsofIvy

Staff Emeritus
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?

There is, in fact, a simple formula for this one: with n points, there are $$\begin{pmatrix}5 \\ 0 \end{pmatrix}+ \begin{pmatrix}n \\ 1\end{pmatrix}+ \begin{pmatrix}n \\ 2 \end{pmatrix}+ \begin{pmatrix}n \\ 3\end{pmatrix}+ \begin{pmatrix}n \\ 4\end{pmatrix}+ \begin{pmatrix}n \\ 5\end{pmatrix}$$ areas.

11. Jul 10, 2013

### jbunniii

You should try it with the stock market!

12. Jul 10, 2013

### Mandelbroth

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
13. Jul 11, 2013

### coolul007

A while ago someone posted something similar about numbers in the Qur'an. This looks similar.