random numbers with a probability

Hi!
I would like to obtain a random number between -15 and +15. And I want in the next row another random number added to the previous number. Till here I have no problem.

=C2+ALEATORIO.ENTRE(-15;15)
or in english
=C2+RAND(-15,15)

The problem is that I want the result being always over 0, always a positive number.
And the biggest problem: I want that the probabilities that 1 or -1 appear is 50%. The probabilities of the appearing of 2 or -2 is 25%, etc.

1---------50%
2---------25%
3---------12.5%
4---------6.25%
5---------3.12%
6---------1.56%
7---------0.78%
8---------0.39%
9---------0.19%
10-------0.09%
11-------0.04%
12-------0.02%
13-------0.01%
14-------0.006%
15-------0.003%

I choose 15 as a limit just to put a limit, but I don’t need it, and could be better if it’s possible all numbers, but with its probability.

Thank you very much for your help,
Caldera

Thanks Shg,
it works in some rows, but other random rows gives me an error #¡NUM!
I don't know why

The formula has no dependence on row, and can only give an error if the value returned by RAND() is exactly zero, which doesn't come up very often. How are you using it?

Here is the worksheet as I'm using it.

You're using RANDBETWEEN(), which is a completely different function than RAND(). Here's the distribution using the second formula for 10,000 random deviates:

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Ok, Shg, now works perfectly.
It was a problem with the traduction. I thought it was the same.

Thank you very much for your help.

You're welcome, glad it worked for you.