Which game is NOT part of the Science Adventure series by 5pb. and Nitroplus?

The game "Occultic;Nine" is not part of the Science Adventure series by 5pb and Nitroplus because it has a different setting and storyline compared to the other games in the series. While the Science Adventure series includes games such as "Chaos;Head," "Steins;Gate," "Robotics;Notes," and "Steins;Gate 0," which all revolve around themes of science, technology, and time travel, "Occultic;Nine" focuses on supernatural and occult elements. Therefore, it does not fit within the overarching narrative and themes of the Science Adventure series.