Find formula from values Is there any "algorithm" or steps to follow to get a formula from a table of values.
Example:
Using this values:
X                Result
1                3
2                5
3                7
4                9

I'd like to obtain:
Result = 2X+1

Edit
Maybe using excel?
Edit 2
Additional info:
It is not going to be always a polynomial and it may have several parameters (I think 2).

Whenever I am asked to find a formula from a range of values, I always use difference patterns.
Do with the data given:
x____________1_______2________3________4
y____________3_______5________7________9
$1^{st}$ diff:___________+2______+2________+2
I know that with the general formula $y = mx + c$  the difference pattern is:
x____________1_______2________3________4
y__________m + c____2m + c____3m + c_____4m + c
$1^{st}$ diff:_________+m______+m _______+m
So the first difference pattern is equal to $m$, i.e. $m = 2$.
I can then use $y(1) = m + c$ to find $c$
where $y(1) = 3$, and $m = 2$
$3 = 2 + c$
therefore $c = 1$
and putting it all together we get $y = 2x + 1$
You can use further difference patterns for polynomials such as $2^{nd}$ diff for $x^2$, $3^{rd}$ diff for $x^3$, etc. but note that for an exponential function you will need to look at a common ratio, rather than a difference pattern.
