Did a simple search to see if this was mentioned before, but happened across some additional, unused experience formulas within Pocket Monsters Stadium. They're both very similiar, the only difference being the multiplier against the squared level.

1: (3/4 lvl^3) + (lvl^2 *10) - 30: 849970 exp at lvl 100
2: (3/4 lvl^3) + (lvl^2 *20) - 30: 949970 exp at lvl 100

Obviously these are unused, but it is still a neat point of interest. I take it they're also present in GB games?