word usage - This is the first post of the series / This is the first post in the series

When writing a series in a blog, with which of the following sentences could you start the first sentence? Are they all correct, is only one correct, are there semantic or only aesthetic differences?
'...' = the title of the series

1. This is the first post of the '...' series.


2. This is the first post in the '...' series.


3. This is the first post of the series '...'.


4. This is the first post in the series '...'.