Geometric progression
In mathematics, a geometric progression is a sequence of numbers such that the quotient of any two successive members of the sequence is a constant. For instance, the sequence 3, 6, 12, 24, 48, ... is a geometric progression with common quotient 2. A geometric progression has exponential growth (or decay).If the initial term of a geometric progression is a and the common quotient of successive members is r, then the n-th term of the sequence is given by a rn, n = 0, 1, 2, ...
The sum of the numbers in a geometric progression is called a geometric series. A convenient formula for geometric series is available: