It's a type of hemstitch. You can learn to do it on your sewing machine by consulting Carol Ahles book, Fine Machine Sewing. Beyond learning how to do machine heirloom techniques like this one, this is the book that taught me how to sew more accurately and the effect fabric grain has on seams and topstitching.
I hope this helps you out.
https://www.amazon.com/Fine-Machine-Sewing-Revised-Embellishing/dp/1561585866