Sequence Decifer

Given 3 integers $a$, $b$ and $c$, find a general formula $f$ that solves $f(1) = a$, $f(2) = b$ and $f(3) = c$.

Usage

From a terminal, inside the folder containing the executable, run the following command:

./sequenceDecifer a b c n

And the general formula, along with other info about the sequence, will be printed in the terminal.

$n$ is an optional argument, that changes the variable character for the formula to show. Default is n, but if you like $x$ as usual polynomial, or any other, you can change it.