In mathematics, an **arithmetic progression** (AP) or **arithmetic sequence** is a sequence of numbers such that the difference between the consecutive terms is constant. For instance, the sequence 5, 7, 9, 11, 13, … is an arithmetic progression with common difference of 2.

If the initial term of an arithmetic progression is and the common difference of successive members is *d*, then the *n*th term of the sequence is given by:

and in general

A finite portion of an arithmetic progression is called a **finite arithmetic progression** and sometimes just called an arithmetic progression. The sum of a finite arithmetic progression is called an **arithmetic series**.

The behavior of the arithmetic progression depends on the common difference *d*. If the common difference is:

- Positive, the members (terms) will grow towards positive infinity.
- Negative, the members (terms) will grow towards negative infinity.

### Famous quotes containing the words arithmetic and/or progression:

“Under the dominion of an idea, which possesses the minds of multitudes, as civil freedom, or the religious sentiment, the power of persons are no longer subjects of calculation. A nation of men unanimously bent on freedom, or conquest, can easily confound the *arithmetic* of statists, and achieve extravagant actions, out of all proportion to their means; as, the Greeks, the Saracens, the Swiss, the Americans, and the French have done.”

—Ralph Waldo Emerson (1803–1882)

“Measured by any standard known to science—by horse-power, calories, volts, mass in any shape,—the tension and vibration and volume and so-called *progression* of society were full a thousand times greater in 1900 than in 1800;Mthe force had doubled ten times over, and the speed, when measured by electrical standards as in telegraphy, approached infinity, and had annihilated both space and time. No law of material movement applied to it.”

—Henry Brooks Adams (1838–1918)