An integer sequence is a sequence whose terms are integers. The most complete printed references for such
sequences are Sloane (1973) and its update, Sloane and Plouffe (1995). The sequences
from both works are included in the vastly expanded On-Line Encyclopedia of Integer
Sequences, founded by Neil Sloane (2003) and maintained by The OEIS Foundation Inc.
(https://oeis.org/). In this listing, sequences are
identified by a unique 6-digit A-number. Sequences appearing
in Sloane and Plouffe (1995) are ordered lexicographically and identified with a
4-digit M-number, and those appearing in Sloane (1973)
are identified with a 4-digit N-number. To look up sequences,
use the OEIS web interface at https://oeis.org/.
Integer sequences can be analyzed by a variety of techniques (Sloane and Plouffe 1995, p. 26), including the application of a data compression algorithm (Bell
et al. 1990), computation of the discrete
Fourier transform (Loxton 1989), or searching for a linear
recurrence equation connecting the terms or a generating
function producing them. There are also a large number of transformations which
relate integer sequences to one another, including the Euler
transform, exponential transform, Möbius transform, and others (Bower, Sloane).
In the Season 2 episode "Backscatter" (2006) of the television crime drama NUMB3RS,
math genius Charlie Eppes poses a problem of identifying an integer sequence to his
students, one of whom uses Sloane's Online Encyclopedia of Integer Sequences to find
it.