Ah right, I also forgot something else:
2000000 * 2 / ( 1 + 1.000348^(-0.333*(SumDimensions/3)^1.7) ) - 2000000 + 25 * Blocks
Edit: ah damn, it's -2000000 too if you write it like that, corrected again, in fact, I usually have it expressed this way instead, hence the mistake...