What number comes next in this sequence?











up vote
1
down vote

favorite
1












$4, 15, 13, 7, 22, -1, 31, -9, 40, -17, 49$.



What comes next? The answer is $-25$, but why?






sequences-and-series pattern-recognition







share|cite|improve this question







New contributor




stackofhay42 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
















  • 9




    My answer is 42. The reason is that I like the number 42. And there is no one who can prove me wrong. That being said, if I were to try to read the mind of whoever made this problem, I would look at every other term.
    – Arthur
    2 hours ago








  • 1




    Any finite sequence of integers can be continued any way you like. Sometimes there are patterns that suggest that one continuation is more natural than another. I see no such pattern here. If you [edit' the question to tell us where the sequence comes from we may be able to hlep. Otherwise the question will probably be closed.
    – Ethan Bolker
    2 hours ago















up vote
1
down vote

favorite
1












$4, 15, 13, 7, 22, -1, 31, -9, 40, -17, 49$.



What comes next? The answer is $-25$, but why?






sequences-and-series pattern-recognition







share|cite|improve this question







New contributor




stackofhay42 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.
















  • 9




    My answer is 42. The reason is that I like the number 42. And there is no one who can prove me wrong. That being said, if I were to try to read the mind of whoever made this problem, I would look at every other term.
    – Arthur
    2 hours ago








  • 1




    Any finite sequence of integers can be continued any way you like. Sometimes there are patterns that suggest that one continuation is more natural than another. I see no such pattern here. If you [edit' the question to tell us where the sequence comes from we may be able to hlep. Otherwise the question will probably be closed.
    – Ethan Bolker
    2 hours ago













up vote
1
down vote

favorite
1









up vote
1
down vote

favorite
1






1





$4, 15, 13, 7, 22, -1, 31, -9, 40, -17, 49$.



What comes next? The answer is $-25$, but why?






sequences-and-series pattern-recognition







share|cite|improve this question







New contributor




stackofhay42 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











$4, 15, 13, 7, 22, -1, 31, -9, 40, -17, 49$.



What comes next? The answer is $-25$, but why?






sequences-and-series pattern-recognition




sequences-and-series pattern-recognition






share|cite|improve this question







New contributor




stackofhay42 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.











share|cite|improve this question







New contributor




stackofhay42 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









share|cite|improve this question




share|cite|improve this question






New contributor




stackofhay42 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.









asked 2 hours ago









stackofhay42

1163




1163




New contributor




stackofhay42 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.





New contributor





stackofhay42 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.






stackofhay42 is a new contributor to this site. Take care in asking for clarification, commenting, and answering.
Check out our Code of Conduct.








  • 9




    My answer is 42. The reason is that I like the number 42. And there is no one who can prove me wrong. That being said, if I were to try to read the mind of whoever made this problem, I would look at every other term.
    – Arthur
    2 hours ago








  • 1




    Any finite sequence of integers can be continued any way you like. Sometimes there are patterns that suggest that one continuation is more natural than another. I see no such pattern here. If you [edit' the question to tell us where the sequence comes from we may be able to hlep. Otherwise the question will probably be closed.
    – Ethan Bolker
    2 hours ago














  • 9




    My answer is 42. The reason is that I like the number 42. And there is no one who can prove me wrong. That being said, if I were to try to read the mind of whoever made this problem, I would look at every other term.
    – Arthur
    2 hours ago








  • 1




    Any finite sequence of integers can be continued any way you like. Sometimes there are patterns that suggest that one continuation is more natural than another. I see no such pattern here. If you [edit' the question to tell us where the sequence comes from we may be able to hlep. Otherwise the question will probably be closed.
    – Ethan Bolker
    2 hours ago








9




9




My answer is 42. The reason is that I like the number 42. And there is no one who can prove me wrong. That being said, if I were to try to read the mind of whoever made this problem, I would look at every other term.
– Arthur
2 hours ago






My answer is 42. The reason is that I like the number 42. And there is no one who can prove me wrong. That being said, if I were to try to read the mind of whoever made this problem, I would look at every other term.
– Arthur
2 hours ago






1




1




Any finite sequence of integers can be continued any way you like. Sometimes there are patterns that suggest that one continuation is more natural than another. I see no such pattern here. If you [edit' the question to tell us where the sequence comes from we may be able to hlep. Otherwise the question will probably be closed.
– Ethan Bolker
2 hours ago




Any finite sequence of integers can be continued any way you like. Sometimes there are patterns that suggest that one continuation is more natural than another. I see no such pattern here. If you [edit' the question to tell us where the sequence comes from we may be able to hlep. Otherwise the question will probably be closed.
– Ethan Bolker
2 hours ago










2 Answers
2






active

oldest

votes

















up vote
10
down vote



accepted










Break up the sequence into the even ordered terms and odd ordered.






share|cite|improve this answer

















  • 2




    Wow! I was looking for some very complicated patterns, and it is actually so easy.
    – Mark
    2 hours ago


















up vote
3
down vote














  • Firs observation, first term and second term add up to 19, third and fourth add to 20, fifth and sixth add to 21 and so on..


According to that, the the next number is $49+x = 24 implies x = -25$




  • Second observation, second and third terms add to 28, the fourth and fifth add to 29 and so on...


Therefore, you can generate the next number using these two observations anywhere in the sequence.



I know this is not the best way to predict the next number. However, it is not a bad try.



:)






share|cite|improve this answer























    Your Answer





    StackExchange.ifUsing("editor", function () {
    return StackExchange.using("mathjaxEditing", function () {
    StackExchange.MarkdownEditor.creationCallbacks.add(function (editor, postfix) {
    StackExchange.mathjaxEditing.prepareWmdForMathJax(editor, postfix, [["$", "$"], ["\\(","\\)"]]);
    });
    });
    }, "mathjax-editing");

    StackExchange.ready(function() {
    var channelOptions = {
    tags: "".split(" "),
    id: "69"
    };
    initTagRenderer("".split(" "), "".split(" "), channelOptions);

    StackExchange.using("externalEditor", function() {
    // Have to fire editor after snippets, if snippets enabled
    if (StackExchange.settings.snippets.snippetsEnabled) {
    StackExchange.using("snippets", function() {
    createEditor();
    });
    }
    else {
    createEditor();
    }
    });

    function createEditor() {
    StackExchange.prepareEditor({
    heartbeatType: 'answer',
    convertImagesToLinks: true,
    noModals: true,
    showLowRepImageUploadWarning: true,
    reputationToPostImages: 10,
    bindNavPrevention: true,
    postfix: "",
    imageUploader: {
    brandingHtml: "Powered by u003ca class="icon-imgur-white" href="https://imgur.com/"u003eu003c/au003e",
    contentPolicyHtml: "User contributions licensed under u003ca href="https://creativecommons.org/licenses/by-sa/3.0/"u003ecc by-sa 3.0 with attribution requiredu003c/au003e u003ca href="https://stackoverflow.com/legal/content-policy"u003e(content policy)u003c/au003e",
    allowUrls: true
    },
    noCode: true, onDemand: true,
    discardSelector: ".discard-answer"
    ,immediatelyShowMarkdownHelp:true
    });


    }
    });






    stackofhay42 is a new contributor. Be nice, and check out our Code of Conduct.










     

    draft saved


    draft discarded


















    StackExchange.ready(
    function () {
    StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3012130%2fwhat-number-comes-next-in-this-sequence%23new-answer', 'question_page');
    }
    );

    Post as a guest















    Required, but never shown

























    2 Answers
    2






    active

    oldest

    votes








    2 Answers
    2






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes








    up vote
    10
    down vote



    accepted










    Break up the sequence into the even ordered terms and odd ordered.






    share|cite|improve this answer

















    • 2




      Wow! I was looking for some very complicated patterns, and it is actually so easy.
      – Mark
      2 hours ago















    up vote
    10
    down vote



    accepted










    Break up the sequence into the even ordered terms and odd ordered.






    share|cite|improve this answer

















    • 2




      Wow! I was looking for some very complicated patterns, and it is actually so easy.
      – Mark
      2 hours ago













    up vote
    10
    down vote



    accepted







    up vote
    10
    down vote



    accepted






    Break up the sequence into the even ordered terms and odd ordered.






    share|cite|improve this answer












    Break up the sequence into the even ordered terms and odd ordered.







    share|cite|improve this answer












    share|cite|improve this answer



    share|cite|improve this answer










    answered 2 hours ago









    TurlocTheRed

    723110




    723110








    • 2




      Wow! I was looking for some very complicated patterns, and it is actually so easy.
      – Mark
      2 hours ago














    • 2




      Wow! I was looking for some very complicated patterns, and it is actually so easy.
      – Mark
      2 hours ago








    2




    2




    Wow! I was looking for some very complicated patterns, and it is actually so easy.
    – Mark
    2 hours ago




    Wow! I was looking for some very complicated patterns, and it is actually so easy.
    – Mark
    2 hours ago










    up vote
    3
    down vote














    • Firs observation, first term and second term add up to 19, third and fourth add to 20, fifth and sixth add to 21 and so on..


    According to that, the the next number is $49+x = 24 implies x = -25$




    • Second observation, second and third terms add to 28, the fourth and fifth add to 29 and so on...


    Therefore, you can generate the next number using these two observations anywhere in the sequence.



    I know this is not the best way to predict the next number. However, it is not a bad try.



    :)






    share|cite|improve this answer



























      up vote
      3
      down vote














      • Firs observation, first term and second term add up to 19, third and fourth add to 20, fifth and sixth add to 21 and so on..


      According to that, the the next number is $49+x = 24 implies x = -25$




      • Second observation, second and third terms add to 28, the fourth and fifth add to 29 and so on...


      Therefore, you can generate the next number using these two observations anywhere in the sequence.



      I know this is not the best way to predict the next number. However, it is not a bad try.



      :)






      share|cite|improve this answer

























        up vote
        3
        down vote










        up vote
        3
        down vote










        • Firs observation, first term and second term add up to 19, third and fourth add to 20, fifth and sixth add to 21 and so on..


        According to that, the the next number is $49+x = 24 implies x = -25$




        • Second observation, second and third terms add to 28, the fourth and fifth add to 29 and so on...


        Therefore, you can generate the next number using these two observations anywhere in the sequence.



        I know this is not the best way to predict the next number. However, it is not a bad try.



        :)






        share|cite|improve this answer















        • Firs observation, first term and second term add up to 19, third and fourth add to 20, fifth and sixth add to 21 and so on..


        According to that, the the next number is $49+x = 24 implies x = -25$




        • Second observation, second and third terms add to 28, the fourth and fifth add to 29 and so on...


        Therefore, you can generate the next number using these two observations anywhere in the sequence.



        I know this is not the best way to predict the next number. However, it is not a bad try.



        :)







        share|cite|improve this answer














        share|cite|improve this answer



        share|cite|improve this answer








        edited 1 hour ago

























        answered 2 hours ago









        Maged Saeed

        527315




        527315






















            stackofhay42 is a new contributor. Be nice, and check out our Code of Conduct.










             

            draft saved


            draft discarded


















            stackofhay42 is a new contributor. Be nice, and check out our Code of Conduct.













            stackofhay42 is a new contributor. Be nice, and check out our Code of Conduct.












            stackofhay42 is a new contributor. Be nice, and check out our Code of Conduct.















             


            draft saved


            draft discarded














            StackExchange.ready(
            function () {
            StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmath.stackexchange.com%2fquestions%2f3012130%2fwhat-number-comes-next-in-this-sequence%23new-answer', 'question_page');
            }
            );

            Post as a guest















            Required, but never shown





















































            Required, but never shown














            Required, but never shown












            Required, but never shown







            Required, but never shown

































            Required, but never shown














            Required, but never shown












            Required, but never shown







            Required, but never shown







            -

            Popular posts from this blog

            A CLEAN and SIMPLE way to add appendices to Table of Contents and bookmarks

            Image
            0 I found a lot of questions abount appendices and ToC. Many users want appendices to be grouped in an Appendix part, however some problems arise with ToC, hyperref, PDF viewer bookmarks, and so on. There are different solutions which require extra packages, command patching and other extra code, however none of them satisfies me. I almost found an easy way to accomplish a good result, where appendices are added to bookmarks in the right way and hyperref links point to the right page. However, the number of the "Appendix" part page is wrong (it's the number of appendix A). Is there any EASY way to fix that? This is a MWE: documentclass{book} usepackage[nottoc,notlot,notlof]{tocbibind} usepackage{hyperref} begin{document} frontmatter tableofcontents mainmatter part{First} chapter{
            Read more

            Calculate evaluation metrics using cross_val_predict sklearn

            Image
            1 In the sklearn.model_selection.cross_val_predict page it is stated: Generate cross-validated estimates for each input data point. It is not appropriate to pass these predictions into an evaluation metric. Can someone explain what does it mean? If this gives estimate of Y (y prediction) for every Y (true Y), why can't I calculate metrics such as RMSE or coefficient of determination using these results? python scikit-learn cross-validation share | improve this question edited Nov 28 '18 at 17:52 desertnaut 20.3k 7 43 79
            Read more

            Insert data from modal to MySQL (multiple modal on website)

            Image
            0 I have problem with inserting data to MySQL from modal. My modal: <a href="#" class="badge badge-pill badge-success">6 komentarzy</a> <a href="#" class="badge badge-pill badge-danger">brak komentarzy</a> <a data-toggle="modal" href="#add_desk_comm_{$desk_['desk_id']}" data-target="#add_desk_comm_{$desk_['desk_id']}" class="ediiit">(dodaj)</a> <div class="modal fade" id="add_desk_comm_{$desk_['desk_id']}" tabindex="-1" role="dialog" aria-labelledby="edit_printer" aria-hidden="true"> <div class="modal-dialog" role="document">
            Read more