Predict the next number following a series of numbers

[Tsjallie]

Hi all!
I have a series of numbers for which I want to forecast the next number.
So if my series of data would be: 10,20,30,40,50,60,70,80,90,100. Then the next number would be 110.
What formula should I use to calculate the 110?
Of course my real data won't be this regular.

[tim201110]

smth like that____________

[Tsjallie]

Yep, exactly what I was looking for!
Almost got there by myself, but was strugling with the extra parameters.
Wasn't aware that the solution for that would be that obvious
Thx!