i just had a sad moment ... i love math.. i love how 3rd number set makes for astronomical missing word here
lets call the dictionary 100k words ... 10x that ... magnitudinal growth ...
also just remembered the abocve missing word.. its the magnitudes..
so i thought, ooh, theres x, *x-n(-1)
alas, no...
not everyone speaks english
the actual answer is more like book of babel