A list of numbers that goes on forever. The numbers have described the terms of the sequence. There is usually some rule which says what the next term will be.

Eg:

1, 3, 5, 7, 9 …

2, 3, 8, 63, 3968 …

0, 3.5, 13, 31.5, 62, 107.5 …

## Arithmetic progression

An arithmetic progression is a sequence of characters in which the distinction between two consecutive numbers is always the same.

**For example** 1, 5, 9, 13, 17 – the difference is always 4. This is called the common difference.

Also called an arithmetic progression or arithmetic sequence.

## Geometric progression or Geometric sequence

A sequence of numbers in which the ration between consecutive numbers is always the same.

eg 2, 6, 18, 54, 162 – the ratio is always 3