INFINIT3!! is a song performed by Akari from 8/pLanet!!.
This song was added to the game on September 16, 2017 for the INFINIT3!! event and the full version was released on October 4, 2017.
When the event ended, it was added to the limited songs roster (it can be played on Mondays, Tuesdays, Thursdays, and Saturdays).