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# Timeline of the OEIS

## Early history

• 1965 Neil Sloane begins collecting integer sequences on file cards, which were later transferred to computer punched cards.
• 1972 Working at AT&T Bell Labs, Neil Sloane completes the manuscript for the Handbook of Integer Sequences.
• 1973 A Handbook of Integer Sequences is published by Academic Press, containing 2372 sequences in lexicographic order and assigned numbers from 1 to 2372. The Handbook only includes sequences of nonnegative integers, sequences containing negative numbers being replaced by their absolute values. Only infinite (or conjectured to be, e.g. Mersenne primes, A000668) sequences are included. The lexicographic order is defined by omitting all initial 0's and 1's and replacing them by a single 1. The initial 1 is added even if it was not in the original sequence.[1]
• 1974 Several supplements to the Handbook are issued and sent to people upon request.

## History

• 1994 The OEIS is available as an email lookup service, including Superseeker.
• 1995 The Encyclopedia of Integer Sequences is published, containing 5488 sequences in lexicographic order and assigned M-numbers from M0000 to M5487. The rules requiring sequences to consist of nonnegative integers and to be infinite (or conjectured to be, e.g. Mersenne primes (A000668) remain in place. The initial 0's and 1's are now preserved, but the first nontrivial term (i.e. exceeding 1) in the sequence must be between 2 and 999, except for the 4 sequences of 0's and 1's M0000 to M0004. The Encyclopedia includes the references to the corresponding sequences (which may differ in their few initial terms) in A Handbook of Integer Sequences as N-numbers from N0001 to N2372 (instead of 1 to 2372.) The Encyclopedia includes the A-numbers that are used in the OEIS, whereas the Handbook did not.
• 1996 The original OEIS website (http://www.research.att.com/~njas/sequences/Seis.html) is launched with 10,000 sequences.
• 1997 The Sequence Fanatics mailing list is started.
• Nov 25 1998 The first edition of the CRC Concise Encyclopedia of Mathematics by Eric W. Weisstein is published, referencing many sequences in the OEIS.
• Summer 1999 With Robin Trew's help, Neil Sloane adds new features to Superseeker, and with a program in C written by Antti Kartonen, he adds a feature to the OEIS which shows numerical arrays in a 2-dimensional format. He also adds an index to the OEIS.
• Nov 1999 Neil Sloane adds an auto-responder for established contributors who fill out the submit or comment form in the OEIS.
• Dec 7 1999 Time-stamping is started.
• Dec 13 1999 Neil Sloane starts a log file for the OEIS.
• Dec 19 1999 Neil Sloane starts a list of works citing the OEIS.
• Jan 07 2001 The OEIS receives its first contribution from Bahrain.
• Jun 03 2001 OEIS WebCam is inaugurated.
• 2002 An Editorial Board is established to help Neil Sloane edit sequences.
• Dec 06 2002 The second edition of the CRC Concise Encyclopedia of Mathematics by Eric W. Weisstein is published, referencing many sequences in the OEIS.
• 2004 The one hundred thousandth sequence is added.
• 2004 Wikipedia creates a template to make it easier to reference sequences in the OEIS from its articles.
• 2006 The classic OEIS search engine is improved.
• May 05 2006 The OEIS is briefly mentioned in an episode of the CBS drama NUMB3RS. The episode, titled "Backscatter," concerns a case involving the Russian mob.
• May 19 2009 The third edition (3 volume set) of the CRC Encyclopedia of Mathematics by Eric W. Weisstein is published, referencing many sequences in the OEIS.
• 2009 The OEIS Foundation is established.
• Oct 26 2009 The OEIS Foundation officially takes over ownership of the OEIS.
• 2009 Tony Noe releases the first cut of OEIS: The Movie.
• 2009 Transition to a wiki begins.
• 2010 The new OEIS website (http://oeis.org) is launched, with the main OEIS (http://oeis.org/classic) and the wiki (http://oeis.org/wiki.)
• 2010 The main OEIS is moved from http://oeis.org/classic to http://oeis.org.
• Oct 10 2010 First "Sequence of the Day"
• Nov 11 2010 The OEIS unveils a custom program for the handling of sequence pages, with the wiki retained for other pages.
• Nov 20 2011 The OEIS adds its two hundred thousandth sequence, A200000.

## Forecast future

• 20652069 The millionth sequence is added.