The On-Line Encyclopedia of Integer Sequences (OEIS), also cited simply as Sloane's, is an online database of integer sequences, created and maintained by N. J. A. Sloane, a researcher at AT&T Labs. In October 2009, the intellectual property and hosting of the OEIS were transferred to the OEIS Foundation. OEIS records information on integer sequences of interest to both professional mathematicians and amateurs, and is widely cited. As of 20 November 2011 (2011 -11-20) it contains over 200,000 sequences, making it the largest database of its kind.
Each entry contains the leading terms of the sequence, keywords, mathematical motivations, literature links, and more, including the option to generate a graph or play a musical representation of the sequence. The database is searchable by keyword and by subsequence.
Read more about On-Line Encyclopedia Of Integer Sequences: History, Non-integers, Conventions, Self-referential Sequences, An Abridged Example of A Typical OEIS Entry, Entry Fields, Searching The OEIS