geometric progression 
noun
A progression of numbers with a constant ratio between each number and the one before (e.g. 1, 3, 9, 27, 81).Another way of obtaining this result is to differentiate both sides of the formula for the sum of a geometric progression....
- One of the worlds growing technological innovation is telecommunications, with its number of punters growing at a geometric progression.
- One knows what happens otherwise: a geometric progression of crime, which neither the courts and nor the prisons are able to cope with.