Evolve to the next triangle numberblock, or the next numberblock that's a member of the step squad. Starts out with 1, 3, 6, 10, 15, 21, 28, 36, 45, 55, 66, 78, 91, 105, 120, 136, 153, and so forth.
This is the final Numberblock-related chain I'm remixing.