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Contents

Small or one-time sequence projects

  1. {{Sequence of the Day for March 1}} through {{Sequence of the Day for March 30}}. Choosing sequences and writing up a sentence or two about one interesting aspect of those sequences.

Large or ongoing sequence projects

  1. Scan journals and books, especially those available on the web, for (a) new sequences (add them!), (b) references to existing sequences (add a reference or link to that entry), and (c) mentions of the OEIS (add them to the list of "Works Citing the OEIS" on the wiki). The following is a partial list of journals and books to look at.
    ARS MATHEMATICA CONTEMPORANEA
    Electronic J. Combinatorics
    Directory of open access journals (clicking on "Browse" on the left then on "Mathematics and Statistics" leads to the mathematical branch)
    Electronic Research Announcements of Amer. Math. Soc.
    European J. Combinatorics
    Experimental Mathematics
    Fibonacci Quarterly
    Integers: Electronic Journal of Combinatorial Number Theory
    J. Chem. Inform. Comput. Sci. (Enumerative chemistry, now renamed as J. Chem. Info. and Modeling)
    J. Integer Sequences
    Nieuw Archief voor Wiskunde
    Royal Society journals
    Wikipedia list of math journals
    Small collection of links
  2. Max Alekseyev, automated discovery of unknown formulae, posting to SeqFan on Oct 25 2011. The project was started in collaboration with Nizhni Novgorod State University, Russia. — Max Alekseyev 12:57, 25 December 2011 (UTC)
  3. Indexing/cross-referencing large [and especially poorly documented/cross-linked] "series", e.g. Decimal expansion of 1/3, 2/3, 1/6, 5/6, 7/6,1/7,......,1/998, (and ultimately all "cons" sequences). — M. F. Hasler 21:48, 24 October 2011 (UTC)
    BTW, this project would merit a page on its own to synchronize / show progress / manage "TO DO's", etc. — M. F. Hasler 21:48, 24 October 2011 (UTC)
  4. Improve the index (since we do not yet have categories), especially
    • for sequences of some 1000+ categories like decimal expansion of ...
    • by wikifying cross references inside the index (e.g. on the above page, "see square roots" or "decagon is spelled 10-gon..." etc.) — M. F. Hasler 03:55, 26 October 2011 (UTC)
    • Perhaps add an index to the hypergeometric recurrences in the spirit of the linear recurrences. Essentially covering all the sequences with a square root in the o.g.f. including many walks, Catalan and Motzkin sequences. — R. J. Mathar 11:46, 14 November 2011 (UTC)
      • Richard, I think this would be a great project, certainly of importance. I'm not sure what the best way to categorize them is (an analogue, hopefully, of your "signature" for linear recurrences) but I've also seen the need. Charles R Greathouse IV 04:26, 31 January 2012 (UTC)
      • Started a section in the "Rea" section of the index under "recurrences, hypergeometric" which uses a major order following the number of terms involved, a minor order following the order of the polynomial of the coeffs., and the integer coeffs. of the polys. from high to low degree. The defining convention is actually that the terms are written poly0*a(n)+poly1*a(n-1)+...=0, because the n-depend. of the poly(i) depend on the agreement on the indexing (increasing, decreasing, offset) of the a(i). Is this the most common formulation of the recurrence? R. J. Mathar 12:41, 29 February 2012 (UTC)
  5. Check terms, add proper names, edit the 2360 unedited sequences.
    The top contributors of uned sequences are Bagula at 74%, Lagneau at 3%, and Shevelev at 2%.
  6. Go through Guy's UPNT and add references (to papers referenced by Guy as well as to UPNT itself, with the section), formulas, and any other relevant material; also add new sequences as needed. I think the best approach would be a distributed project where many people each volunteer to take one or more sections. Charles R Greathouse IV 04:43, 15 March 2012 (UTC)
  7. More important and more urgent: find out the present state of Richard Guy's updates in preparation of the new edition of UPINT! - N. J. A. Sloane, Mar 20, 2013
  8. Create a "community portal" with a corner (or simply a separate page) "TO DO on OEIS", where one could post "request of jobs to be done" (instead of posting to SeqFan list), like: Errors to correct -- Please double-check, I suspect an error in Seq. Annn -- Someone who feels competent, please calculate more terms for Annn concerned with ... [I know, KW "more" essentially means the same...] -- etc. — M. F. Hasler 13:44, 24 August 2012 (UTC)
  9. Create an iOS interface or app; I'm willing to make an OEIS interface for iPhone/iPod touch/iPad. If appropriate, any suggestions on how to access the database from outside? — Jens Bossaert 18:47, 7 April 2013 (UTC)
    I'm curious as to what you'd want the application to do (beyond what the site does, of course). The project sounds interesting and I might be able to help (though I don't have an Apple developer account).
    As for accessing the database, I just use https://oeis.org/search?q=id%3AA000001&fmt=text. Or do you mean something else?
    Charles R Greathouse IV 18:58, 7 April 2013 (UTC)
  10. Insert b-files at the top of the "links" field. If possible automatically move b-file links that are not at the top to the top. - Joerg Arndt 12:27, 25 April 2013 (UTC)
  11. Preserve line breaks in pink-box comments. - Joerg Arndt 12:27, 25 April 2013 (UTC)
  12. Add the keyword "more" where obviously needed. I did that for up to A001500. The file stripped.gz is of great help with this task. — Joerg Arndt 13:56, 21 May 2013 (UTC)
  13. Go through sequences marked keyword:more keyword:easy and either expand or reclassify. - Charles R Greathouse IV 05:44, 19 June 2013 (UTC)

Other

  1. Should journal and book titles in the CiteA, CiteB, ... CiteZ pages be italicized? — Alonso del Arte 15:56, 29 November 2011 (UTC)

Done

  1. (Done) Repair links to SeqFan threads as announced in Re: Early SeqFan archives — R. J. Mathar 18:04, 4 January 2013 (UTC)
  2. (Done) Replace "Vladeta Jovovic (vladeta(AT)eunet.yu)" by "_Vladeta Jovovic_" — Joerg Arndt 13:58, 21 May 2013 (UTC)
  3. (Done) Replace "Frank Ruskey, Nate Kube (ruskey(AT)cs.uvic.ca)" by "_Frank Ruskey_ and Nate Kube" . R. J. Mathar 14:13, 9 May 2013 (UTC)
  4. (Done) Replace the names "A simple regular expression in a labeled universe" by more specific ones. — R. J. Mathar 21:24, 17 November 2011 (UTC)
  5. (Done) The paper V. Jelinek, T. Mansour and M. Shattuck, On multiple pattern avoiding set partitions, Advances in Applied Mathematics Volume 50, Issue 2, February 2013, Pages 292-326 (I have a copy), contains a number of generating functions (See Theorems 4.1, 4.2, Ex. 4.16 (3), 4.17 (2), Prop. 4.20, 4.21, 4.23, 4.27, and maybe others). Could someone produce the sequences corresponding to these g.f.'s and add them to the OEIS if they are new, or add references to this paper if they are already in the OEIS? - N. J. A. Sloane, 1 January 2013. doi:{{{1}}}, Theorem 4.1=A025242. Theorem 4.2=A005773. Ex. 4.16=A005183 and A116701, but H1121 gives negative terms (incorrect), L1121 =A209230 (new, sign corrected). L_{1232}=A005183, same as proposition 4.20. Lemma 4.21=essentially A132750. R. J. Mathar 21:42, 12 January 2013 (UTC)
  6. (Done) Replace http://algo.inria.fr/csolve by http://www.people.fas.harvard.edu/~sfinch/csolve . R. J. Mathar 18:15, 8 January 2013 (UTC)
  7. (Done) Apparently the book M. Pitici, editor, The Best Writing on Mathematics, Princeton Univ. Press, 2012 mentions the OEIS - can someone tell me in which chapter, page numbers, etc.? - N. J. A. Sloane, Jan 02 2013
  8. (Done) Repair references to arxiv esp. by E. Deutsch: already fixed ~ 25 occurrences of "arxiv1111...." to "arxiv:1111..." by hand, but there are about 30 left (cf. https://oeis.org/search?q=arXiv1111&fmt=short), and most probably others (not only(?) from the same submitter). — M. F. Hasler 18:37, 6 January 2013 (UTC)
    I corrected all 26 cases, plus two similar ones I found. Charles R Greathouse IV 18:10, 7 January 2013 (UTC)
  9. (Done) Apparently this paper: Keisuke Nakano, Shall We Juggle, Coinductively?, in Certified Programs and Proofs, Lecture Notes in Computer Science Volume 7679, 2012, pp 160-172, DOI 10.1007/978-3-642-35308-6_14 mentions the OEIS and probably has one or more new sequences in it - does anyone have access to a copy? - N. J. A. Sloane, Jan 02 2013
  10. (Done) Recycle A187733, A187734 etc. up to approximately A187812. R. J. Mathar 20:02, 22 December 2012 (UTC)
  11. (DONE) Replace richardchoulet(AT)yahoo.fr by _Richard Choulet_ — R. J. Mathar 15:59, 19 December 2012 (UTC)
    I instead changed Richard Choulet (richardchoulet(AT)yahoo.fr) and R. Choulet (richardchoulet(AT)yahoo.fr) to _Richard Choulet_. Charles R Greathouse IV 20:53, 19 December 2012 (UTC)
  12. (DONE) Replace Wolfdieter Lang (wolfdieter.lang_AT_physik_DOT_uni-karlsruhe_DOT_de) and W. Lang (wolfdieter.lang_AT_physik_DOT_uni-karlsruhe_DOT_de) by _Wolfdieter Lang_ . R. J. Mathar 11:54, 30 September 2012 (UTC). Replace Roger L. Bagula and Gary W. Adamson (rlbagulatftn(AT)yahoo.com) by _Roger L. Bagula_ and _Gary W. Adamson_ . The same for the case without middle initials. R. J. Mathar 07:44, 9 October 2012 (UTC)
  13. (DONE) Replace Steven.Finch(AT)inria.fr (S. R. Finch) and S. R. Finch (Steven.Finch(AT)inria.fr) by _Steven Finch_ R. J. Mathar 08:03, 10 October 2012 (UTC)
  14. (DONE) Replace Alonso Delarte (alonso.delarte(AT)gmail.com) by _Alonso del Arte_, R. J. Mathar 19:27, 10 October 2012 (UTC)
  15. (DONE) Replace Paul Barry (pbarry(AT)wit.ie by _Paul Barry_
  16. (DONE) Replace Patrick de Geest (pdg(AT)worldofnumbers.com) by _Patrick De Geest_
  17. (DONE) Replace Paolo P. Lava & Giorgio Balzarotti (paoloplava(AT)gmail.com) by _Paolo P. Lava_ and Giorgio Balzarotti
    I used the replacement text _Paolo P. Lava_ and _Giorgio Balzarotti_ instead. - Charles R Greathouse IV 14:53, 24 August 2012 (UTC)
  18. (DONE) Replace M. F. Hasler (www.univ-ag.fr/~mhasler) and Robert G. Wilson (rgwv(AT)rgwv.com) and the same with lowercase (at) and RGWv and rgwv by their _M. F. Hasler_ and _Robert G. Wilson v_ equivalents. R. J. Mathar 10:23, 7 July 2012 (UTC)
    Not all that easy; Wilson's name appears in many forms. I corrected some manually and the others with global edits. Both should be done now. Charles R Greathouse IV 19:32, 14 July 2012 (UTC)
  19. (DONE) Replace links to Steven Finch's algo.inria.fr/bsolve/ , which moved, by www.people.harvard.edu/~sfinch/ R. J. Mathar 21:18, 29 June 2012 (UTC)
  20. (Basically done by previous work by Brockhaus and Lava) Add the surds to all periodic sequences for which the sequences are the continued fractions (if all terms in the period are > 0). — R. J. Mathar 13:33, 21 November 2011 (UTC)
  21. (DONE) Replace dml(AT)hpfrcu03.france.hp.com by patrick.demichel(AT)hp.com R. J. Mathar 15:17, 24 February 2012 (UTC)
  22. (DONE) Fix ~30 tabf sequences not marked tabf.
  23. (DONE) Please replace http://www.mscs.dal.ca/~joerg/res/fq.html with http://www1.uni-hamburg.de/RRZ/W.Keller/FermatQuotient.html everywhere in the OEIS. Thanks! Max Alekseyev 04:32, 30 January 2012 (UTC)
  24. (DONE) Replace pierrecami(AT)tele2.fr by pierre-cami(AT)bbox.fr — R. J. Mathar 14:16, 30 November 2011 (UTC)
  25. (DONE) Please replace http://www.cs.ucsd.edu/users/maxal/gpscripts/ with http://cse.sc.edu/~maxal/gpscripts/ everywhere in the OEIS. Thanks! — Max Alekseyev 10:47, 1 December 2011 (UTC)
  26. (DONE) Replace the ca 970 broken links to algo.inria.fr/bin/encyclopedia by equivalent ref to algo.inria.fr/ecs — R. J. Mathar 18:07, 27 November 2011 (UTC)
  27. (DONE) How should we celebrate reaching 200000 sequences, which will happen soon? (Back in 2004 when we reached 100000 sequences we held an eParty - see https://oeis.org/100k.html.) — N. J. A. Sloane, Oct 26 2011
    I wonder if we should hold off and celebrate a quarter-million instead. In any case I think you should reserve A200000 and make it something special (like A100000). — Charles R Greathouse IV 15:11, 10 November 2011 (UTC)
    I reserved A200000 and am looking for suggestions for an appropriate sequence — N. J. A. Sloane, Nov 14 2011
    I just created a link to that page, suggestions for an appropriate sequence — M. F. Hasler 20:28, 14 November 2011 (UTC) (DONE)
  28. (DONE) Coming up with better names for all sequences titled "See [computer program] for definition." There are about half a dozen such sequences for Mathematica, there may be some for programs not meant for number theory (such as VBScript for Microsoft Excel) or obscure programming languages like UBasic.
  29. (DONE) Adding sequences listing arithmetic progressions of squares. The following papers are relevant: http://www.math.uconn.edu/~kconrad/blurbs/ugradnumthy/3squarearithprog.pdf and http://www.math.uconn.edu/~kconrad/blurbs/ugradnumthy/4squarearithprog.pdf Work has begun on A198384 — A198390
    I'm hinting that the idea could be generalized to quadratic progressions of cubes, cubic progressions of fourth powers, ... — Daniel Forgues 01:15, 27 October 2011 (UTC)
  30. (DONE) Sequences pertaining to rows, columns and diagonals of Ulam's spiral (2010)
  31. (DONE) The paper V. Alvarez, J. A. Armario, M. D. Frau and F. Gudlel, The maximal determinant of cocyclic (-1, 1)-matrices over D_{2t}, Linear Algebra and its Applications, 2011, in press; doi:10.1016/j.laa.2011.05.018 references the OEIS, but I don't have access to it. If it contains a new sequence then that should be added to the OEIS. If it cites an existing sequence then we should add a reference from that sequence to this paper. Can someone look into this? — N. J. A. Sloane, Oct 28 2011. The URL is http://www.sciencedirect.com/science/article/pii/S002437951100423X
    Table 1:
    Proportion of inequivalent Hadamard matrices (cocyclic/general framework).
    n 4 8 12 16 20 24 28 32 36
    #[CH] 1 1 1 5 3 16 6 100 35
    # [H] 1 1 1 5 3 60 487
    If we attend to the summation of the number of Hadamard matrices equivalent to a matrix of [H] and [CH] in Table 1, denoted by #H and #CH respectively (the required information may be extracted from [27] and [32]), we obtain Table 2."
    Table 2:
    Proportion of Hadamard matrices belonging to equivalence classes [CH] and [H].
    n 4 8 12 16 20 24 28
    #CH 192 21,504 190,080 10,838,016 16,440 790,224 64,488
    #H 192 21,504 190,080 10,838,016 16,440 823,616 74,306
    [27] P. Ó Catháin, M. Röder, The Cocyclic Hadamard matrices of order less than 40, Des. Codes Cryptogr. 58 (1) (2011) 73–88.
    [32] N.J.A. Sloane, A Library of Hadamard Matrices (website), http://www2.research.att.com/~njas/hadamard/.
    [33] N.J.A. Sloane, The On-line Encyclopedia of Integer Sequences (website), http://oeis.org/."
    — Jason Kimberley 09:43, 31 October 2011 (UTC). DONE!
  32. (DONE) Same thing for this paper: Heng Huat Chan,Yoshio Tanigawa, Yifan Yang and Wadim Zudilin, New analogues of Clausen's identities arising from the theory of modular forms, Advances in Mathematics, Volume 228, Issue 2, 1 October 2011, Pages 1294-1314; doi:10.1016/j.aim.2011.06.011; http://www.sciencedirect.com/science/article/pii/S0001870811002003.
    S_n = \binom{2n}{n} \sum_{k=0}^{n} \binom{n}{k^2} \binom{2k}{k}. \,
    In this case, the sequence {Sn} matches nicely with a sequence in [20].
    [20] N.J.A. Sloane, The on-line encyclopedia of integer sequences, published electronically at http://oeis.org, 2010.
  33. (DONE) Same thing for this paper: G. Le Caer, A New Family of Solvable Pearson-Dirichlet Random Walks, Journal of Statistical Physics, Volume 144, Number 1, 23-45, DOI: 10.1007/s10955-011-0245-4; http://www.springerlink.com/content/4225546845h58j2h/.
    Added reference to A100861. — Charles R Greathouse IV 13:52, 31 October 2011 (UTC) (DONE)
  34. (DONE) Same thing for this paper: C. Phatak, R. Pokharel, M. Beleggia and M. De Graef, On the magnetostatics of chains of magnetic nanoparticles, Journal of Magnetism and Magnetic Materials, Volume 323, Issue 22, November 2011, Pages 2912-2922; http://www.sciencedirect.com/science/article/pii/S0304885311004124. I don't have access to it. If it contains a new sequence then that should be added to the OEIS. If it cites an existing sequence then we should add a reference from that sequence to this paper. Can someone look into this? — N. J. A. Sloane, Oct 28 2011.
    This magnetostatics paper does not cite any specific sequence: "By expanding these hypergeometric functions and extensively using Sloane's Encyclopedia of Integer Sequences [21], we arrive at ...". It does not seem to contain any new sequences. — Jason Kimberley 09:43, 31 October 2011 (UTC). DONE.
  35. (DONE) # The following paper apparently references the OEIS, but I do not have access to it. If it contains a new sequence then that should be added to the OEIS. If it cites an existing sequence then we should add a reference from that sequence to this paper. Can someone look into this? — N. J. A. Sloane, Nov 01 2011: Lisa Glaser, Causal set actions in various dimensions, Journal of Physics: Conference Series, 2011; J. Phys.: Conf. Ser. 306 012041 doi:10.1088/1742-6596/306/1/012041; http://iopscience.iop.org/1742-6596/306/1/012041. Nov 03: I now have a copy of this paper. (DONE)
  36. (DONE) # The following paper apparently references the OEIS, but I do not have access to it. If it contains a new sequence then that should be added to the OEIS. If it cites an existing sequence then we should add a reference from that sequence to this paper. Can someone look into this? — N. J. A. Sloane, Nov 02 2011: Kentaro Ihara, Derivations and automorphisms on non-commutative power series, Journal of Pure and Applied Algebra, Volume 216, Issue 1, January 2012, Pages 192-201; doi:10.1016/j.jpaa.2011.06.004; http://www.sciencedirect.com/science/article/pii/S0022404911001484. Nov 03: I now have a copy of this paper. (DONE)
  37. (DONE) # The following paper apparently references the OEIS, but I do not have access to it. If it contains a new sequence then that should be added to the OEIS. If it cites an existing sequence then we should add a reference from that sequence to this paper. Can someone look into this? — N. J. A. Sloane, Nov 01 2011: Anders Claesson and Svante Linusson, "n! matchings, n! posets", Proc. Amer. Math. Soc. 139 (2011), 435-449; http://www.ams.org/journals/proc/2011-139-02/S0002-9939-2010-10678-0/home.html. Nov 03: I now have a copy of this paper. (DONE)
  38. (DONE) The following paper apparently references the OEIS, but I do not have access to it. If it contains a new sequence then that should be added to the OEIS. If it cites an existing sequence then we should add a reference from that sequence to this paper. Can someone look into this? — N. J. A. Sloane, Nov 02 2011: R. R. Birss, The Saturation Magnetostriction of Ferromagneties, Advances in Physics, Vol. 8, issue 31, [1959], pp. 252-291; DOI:10.1080/00018735900101198; http://www.tandfonline.com/doi/abs/10.1080/00018735900101198.
    There seem to be no OEIS-worthy sequences in this. There are very short rational expansions of some tensorial expressions related to the space-group symmetries in crystals. — R. J. Mathar 16:12, 6 November 2011 (UTC) (DONE)
  39. (DONE) The following paper apparently references the OEIS, but I do not have access to it. If it contains a new sequence then that should be added to the OEIS. If it cites an existing sequence then we should add a reference from that sequence to this paper. Can someone look into this? — N. J. A. Sloane, Oct 28 2011. The paper is: XiKun Li, JunLi Li, Bin Liu and CongFeng Qiao, The parametric symmetry and numbers of the entangled class of 2 × M × N system, SCIENCE CHINA PHYSICS, MECHANICS & ASTRONOMY, Volume 54, Number 8, 1471-1475, DOI: 10.1007/s11433-011-4395-9; http://www.springerlink.com/content/24g51u87527017u7/. Nov 03 2011: I now have a copy of this paper. (DONE)
  40. (DONE) The following paper apparently references the OEIS, but I do not have access to it. If it contains a new sequence then that should be added to the OEIS. If it cites an existing sequence then we should add a reference from that sequence to this paper. Can someone look into this? — N. J. A. Sloane, Oct 28 2011. The paper is: Eddie Cheng, Ke Qiu and Zhizhang Shen, On the surface area of the augmented cubes, J. of Supercomputing, DOI: 10.1007/s11227-011-0641-1; http://www.springerlink.com/content/980453w252uvn23j/. Nov 03: I now have a copy of this paper. (DONE)
  41. (Done) Replace njas(AT)research.att.com by njasloane(AT)gmail.com — R. J. Mathar 13:11, 25 February 2012 (UTC)
    This is too big of a project for me; maybe Russ should get involved. It seems that the global edit system can't handle a change that large -- we've done two edits with over 3000 but this has better than 42,000. Charles R Greathouse IV 05:18, 26 February 2012 (UTC)
    See Neil Sloane, Change of email address in OEIS, posting to SeqFan on Feb 28 2012.

Not done

  1. Reducing all (or most) b-files to the standard size (10000?). [From Moshe Levin]
    I strongly disagree. The b-files should never be shortened. — N. J. A. Sloane, Oct 25 2011
    Maybe extending when possible b-files to a thousand or ten thousand terms (as recently happened with A065449 with a b-file that went up to 466, so Charles extended it to 1000. [From Alonso del Arte 20:02, 24 October 2011 (UTC)]
    This has been discussed earlier, see also http://oeis.org/wiki/User_talk:M._F._Hasler/dynamic_content#The_basic_idea: If there is an excessively large b-file, it would indeed be useful to have b-file(s) of handier size, which could be created by the server (either physically as a file or virtually/dynamically "upon request"), by simply truncating the existing one. — M. F. Hasler 19:59, 24 October 2011 (UTC)


See also

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