There is one major difference between the two combinations. In the open stitch combination, the double crochet stitches are worked into the previous row's double crochet stitches. In the seed stitch, single crochet stitches are worked in the previous row's chain stitches.
To make it, chain a multiple of two plus one.
One thing that I wasn't a fan of when trying this stitch out was that one side of the pattern creates a zig zagged edge. Perhaps a slip stitch at the end of row 2 (to attach it to row 1) in the pattern diagrm above would help solve this.
This stitch could also be done by changing the single crochet stitch for a taller stitch, like the double or treble crochet stitches.
What are your thoughts about this stitch? Have you seen it used in any patterns you've worked on?