Geometric sequence problem with the last term (2018) undetermined. 
$x_0 = 1$
$x_{n+1}=2x_{n}+1$
$S_n=x_0+x_1+\ldots+x_n$
$\text {Find } S_{2018}$ 

How can I solve it?
I tried to understand the sum of sequence but I couldn't and this is what I got:
$$1+3+7+15+31+\ldots$$
I really don't know how to calculate the $2018^{\text {th}}$ term. Can anyone help me?

Hint:
Write the sequence $x_0+1$, $x_1+1$, $x_2+1$, $x_3+1$, ...
