Imagine an advanced alien race that seeded a planet with species capable of written communication. While the alien race is on the planet for a few generations it wants to remain mostly hidden from the species. But before it leaves it wants the species to be able to:
- Find out who seeded them
- Find the alien race across the universe
- Travel to the alien race across the universe
But only after the species has advanced significantly enough to build computational power of a certain level since the FTL travel technology requires more computational power than the computers in the rockets from the '60s.
How would an alien race hide information about its presence, location, and FTL travel before the species was ready for it? Specifically could this information be encoded in some written communication that wouldn't be discovered (the information not the communication) till the species could find patterns in said communication through their advanced computational power?