## Arithmetic Sequence Definition

definition: a_{n} = a_{1} + f × (n-1)

example: 1, 3, 5, 7, 9 11, 13, ...

Arithmetic progression is a sequence of numbers in which each differs from the preceding one by a constant quantity (e.g. 1, 2, 3, 4, etc.; 9, 7, 5, 3, etc.).

This constant difference is called common difference.each member of progression can be expressed as

Sum of the n members of arithmeic progression can be expressed as