That's usually called a "Hammer In" or "Snap In" or "Barbed" weatherstrip. Maybe one of those terms will help with on internet search.
Look carefully at both vertical jambs and, with a mirror, the bottom and top jambs. With luck the manufacturer's name & the door model number will be printed on the door and serve as a source for the seal. Sometimes it's printed under a hinge leaf.
There is a company called Universal Weatherstrip & Building Supply that has been around here for more than 100 years. They have just about every kind of weather sealing item possible. Universalweatherstrip.com is the web site. Their phone number is (313) 534-8049. Maybe they have it, can get it for you or at least identify it.
Hope This Helps!
Paul