Create a pattern with the rule n x 2 + 1

To create this pattern, you can start with the number zero and apply this math.  0 x 2 +1 = 1.  The next number would be found by taking 1 x 2 + 1=3.  After that 3 x 2 + 1 = 7.  The next number in the pattern would be found by taking 7 x 2 +1.  Essentially, you are just taking the answer you just got and doubling it and then adding 1.  Here is the pattern that would be created beginning with 0.  0, 1, 3, 7, 15, 31, 63, etc...

The second and fourth answer are correct