The OEIS Foundation Inc. Other ways to Give The OEIS Foundation Inc. On this page: Goals of OEIS Foundation Description of OEIS® How the OEIS is used History of OEIS The new OEIS More about goals of Foundation The OEIS Foundation Advisory Board Tax-exempt status and other legal documents Tax-exempt status in New Jersey Transfer of IP to OEIS Foundation Trademarking “OEIS” Financial reports Fundraising Committee List of donors The OEIS posters The OEIS Movie To contact the OEIS Foundation Related Pages: To donate to OEIS Foundation Jan 1 2010: OEIS Moves to a New Home Nov 17 2010: New Version of OEIS! Dec 2 2011: OEIS reaches 200,000 sequences Articles of Incorporation Bylaws of Foundation Trustees of Foundation Advisory Board Change of Registered Agent Related Pages (continued): Filing Articles Form 1023, Supplementary information Letter from IRS, Aug. 19 2009 Reply to IRS Tax-exempt status approved by IRS Registration as NJ Charity NJ Charity Acceptance Exemption from NJ business tax Exemption from NJ sales and use tax NJ Sales Tax Exempt Certificate Letter of assignment to OEIS Foundation “OEIS” trademark Requirements for 2011-2021 “OEIS” trademark renwed February 2021 “The On-Line Encyclopedia of Integer Sequences” trademark Requirements for 2011-2021 Conflict of Interest Policy Review of Financial Reports Expenses Reimbursement Policy Gift Acceptance Policy Record Retention, Destruction Policy Whistle Blower Policy OEIS Contributor’s License Agreement OEIS End-User License Agreement OEIS Terms of Use Goals of The OEIS Foundation Inc. The OEIS Foundation Inc. is a New Jersey nonprofit corporation (#0101000611; Articles of incorporation filed with the State of New Jersey, April 14 2009; EIN 30-0562250) whose main goals are the following four items: To own the intellectual property known as “The On-Line Encyclopedia of Integer Sequences®” (or “OEIS®”). To maintain the OEIS as a service that is freely accessible by the general public. To act so as to maintain its own existence indefinitely. To collect and distribute funds in order to carry out the first three goals. These goals are described in greater detail in a later section of this web page, and in the Articles of Incorporation and Bylaws. To facilitate the fourth goal, The OEIS Foundation Inc. has been approved by the Internal Revenue Service as a charity and a Section 501(c)(3) tax-exempt organization. For details please see the section on Tax-exempt status. Tax-deductible donations to The OEIS Foundation Inc. can be made through PayPal using the icon at the top right of this page (see also below). Note: Except when used in the name of this corporation (The OEIS Foundation Inc.), the word “OEIS” is an abbreviation for “The On-Line Encyclopedia of Integer Sequences®”. Description of The On-Line Encyclopedia of Integer Sequences® (or OEIS®) The On-Line Encyclopedia of Integer Sequences® (OEIS®) is the on-line version of a database of sequences of numbers which will soon be celebrating its 50th anniversary. A conventional dictionary is a collection of words, together with explanations of their meanings, hints for their pronunciation, pictures illustrating particular words, examples showing how the words have been used in books and newspapers, and so on. The OEIS is a collection of sequences of numbers (such as 1, 2, 4, 8, 16, 32, 64, 128, …) together with, for each sequence, a list of items such as: The first 10, or 10,000, or sometimes 500,000 terms of the sequence A definition or description of the sequence Comments explaining further properties of the sequence Formulas for generating the sequence Computer programs for generating the sequence References to books and articles where the sequence has appeared Links to web pages on the Internet where the sequence has appeared Cross-references to related entries in the OEIS The name of the person who submitted the sequence to the OEIS Further names of people who have added additional information about the sequence Examples illustrating some of the terms of the sequence (for example, sequence A124. which gives the maximal number of pieces that can be obtained when cutting a circular pancake with n cuts, is illustrated with pictures showing the pieces obtained with n = 1, 2, 3, 4 and 5 cuts) The history of each sequence in the OEIS as it has evolved over time Users of the OEIS may also view graphs or plots of each sequence, or to listen to the sequence when it is converted to music The OEIS currently contains about 300,000 entries (although that number will be out-of-date by the time you read it). These have been distilled from many sources - books, journals, articles, and letters and electronic mail messages from thousands of contributors. Since November 11, 2010, users have been able to use the Internet to submit contributions to the OEIS. All submissions are refereed. How the OEIS is used The main use for the OEIS is to identify a number sequence that you have come across, perhaps in your work, while reading a book, or in a quiz, etc. For example, you discover what you think may be a new algorithm for checking that a file of medical records is in the correct order. (Perhaps you are a computer scientist or someone working in information science.) To handle files of 1, 2, 3, 4, … records, your algorithm takes 0, 1, 3, 5, 9, 11, 14, 17, 25, … steps. How can you check if someone has discovered this algorithm before? You decide to ask the OEIS if this sequence has appeared before in the scientific literature. You go the OEIS web site, enter the numbers you have calculated, and click “Submit”. The reply tells you that this is sequence A3071, which is the number of steps needed for “sorting by list merging”, a well-known algorithm. The entry directs you to Section 5.3.1 of Volume 3 of D. E. Knuth, “The Art of Computer Programming”, where you find your algorithm described. The entry even gives an explicit formula for the nth term. You decide not to apply for a patent! The OEIS web site includes a list of some 4500 articles, books, theses, etc., that have acknowledged help from the OEIS. For further information about the OEIS, see the OEIS Welcome Page, the Lookup Page, the Demonstration Pages, or the Wikipedia article. History of the OEIS The collection was begun by Neil J. A. Sloane (henceforth, “NJAS”) in 1964 when he was a graduate student at Cornell University in Ithaca NY. He had encountered a sequence of numbers while working on his dissertation, namely 1, 8, 78, 944, … (now entry A435. in the OEIS), and was looking for a formula for the n-th term, in order to determine the rate of growth of the terms. He noticed that although several books in the Cornell library contained sequences somewhat similar to this, this particular sequence was not mentioned. In order to keep track of the sequences in these books, NJAS started recording them on file cards, which he sorted into lexicographic order. The sequences were transferred to punched cards in 1967, and were made into a book in 1973 (“A Handbook of Integer Sequences”, by NJAS, Academic Press, NY). NJAS joined AT&T Bell Laboratories in 1969. Following the publication of the book, a large amount of correspondence ensued, with suggestions for further sequences and updates to the existing entries. Many people remarked how useful they found the book, and how surprising it was that no one had published such a collection before. By the early 1990’s over a cubic meter of correspondence had accumulated. A Canadian mathematician, Simon Plouffe, offered to help in preparing a revised edition of the book, and in 1995 “The Encyclopedia of Integer Sequences”, by NJAS and Simon Plouffe, was published by Academic Press, San Diego. (Simon Plouffe is now one of the Trustees of The OEIS Foundation Inc.) The 1973 book contained 2372 sequences, and the 1995 book 5487 sequences, occupying 587 pages. Again, once the book appeared, many further sequences and updates were submitted from people all over the world. NJAS waited a year, until the size of the collection had doubled, to 10,000 entries, and then in 1996 he launched the On-Line Encyclopedia of Integer Sequences on the Internet. From 1996 until November 11, 2010, this was part of NJAS’s home page on the AT&T Labs Web Site. Since 1996, the collection has grown by 10,000 to 18,000 entries per year. At the present time (May 29, 2013) there are 225,735 entries. If it were to be published in book form today, it would require at least 750 volumes the size of the 1995 book. Starting in 2002, NJAS added a group of associate editors to help process submissions to the OEIS. However, because they did not have access to the computer where the OEIS was maintained, almost all the work of updating it had to be done single-handedly by NJAS. This involved processing 100 or 200 emails every day, and was getting to be beyond what one person could handle. In January 2009, therefore, it was decided to make a drastic change. We (NJAS and the associate editors) made a plan to convert the OEIS into a “wiki” format, somewhat along the lines of the well-known Wikipedia, which would be hosted by a commercial hosting service. (A copy of a letter of consent from AT&T agreeing to this course of action is available on request from NJAS.) It was also decided to set up the OEIS Foundation, the goals of which would be to own, maintain and raise funds to support the new version of the OEIS. Most of this went smoothly. The OEIS Foundation Inc. was incorporated in the State of New Jersey on April 14, 2009. We rented space on a commercial hosting service, and tried to move the OEIS to the new site. Here, however, we ran into a very serious problem. In the summer of 2009, when we tried to get the OEIS working as a wiki, we discovered that the Mediawiki software was not capable of handling the kind of queries that arise in looking up sequences. This was a disaster. It took us over a year to resolve this problem. In the end, Russ Cox completely rewrote all the programs needed to maintain the database and answer queries - a huge task! NJAS’s colleague David Applegate has also been of enormous help in getting the new system working. As a result of their work, the new OEIS was finally launched on November 11, 2010. (For more details, see the attached announcement.) It is now possible for anyone in the world to propose a new sequence or an update to an existing sequence. To do this, users must first register. A group of about 130 editors has been formed, whose job it is to review submissions before they become a permanent part of the OEIS. So, after nearly two years of struggle, the OEIS was finally able to operate without NJAS having to approve every change. After 46 years of running the database, this came as a great relief to him. The new OEIS As mentioned in the previous paragraph, the OEIS was successfully launched in its new home (http://oeis.org) on November 11, 2010. At this time it contained 180,284 sequences. In the first full year of operation, from Nov 11 2010 to Dec 1 2011, 19716 new sequences were accepted, an average of over 50 per day, and there were about 250 edits per day of existing sequences. We now have over 20 Editors-in-Chief and over 80 Associate Editors, and about 2000 registered users (see here for these lists). The following is a summary of the traffic on the new web site for the months of December 2010 and September 2015. The first four columns are the daily average, the last six columns are the total for the month. (These figures don’t mean much, since most of the traffic comes from web-crawlers, but are shown here because people often ask for them. The figures are lower for 2015 presumably because now the web-crawlers are only downloading pages that have changed.) …