Integer sequence

An integer sequence may be specified explicitly by giving a formula for its n-th term, or implicitly by giving a relationship between its terms. For example, the sequence 1, 1, 2, 3, 5, 8, 13, ... (the Fibonacci sequence) is formed by starting with two ones and then adding any two consecutive terms to obtain the next one: an implicit description. The sequence 0, 3, 8, 15, ... is formed according to the formula n² - 1 for the n-th term: an explicit definition.

External Resources:

• Information about thousands of integer sequences is recorded in Neil Sloane's Encyclopedia of Integer Sequences, online at http://www.research.att.com/~njas/sequences/ (http://www.research.att.com/~njas/sequences/).