Density of twin square-free numbersare there infinitely many triples of consecutive square-free...



Density of twin square-free numbers


are there infinitely many triples of consecutive square-free integers?Squarefree numbers $n$ such that $432n+1$ is also squarefreeorthogonality relation for quadratic Dirichlet charactersInfinite sets of primes of density 0A pair of subset of natural numbers having density, but whose intersection has no densityDensity of numbers whose prime factors all come from a fixed congruence classThe density of square-free integers represented by a cubic polynomialIf the natural density (relative to the primes) exists, then the Dirichlet density also exists, and the two are equalExistence of relative Dirichlet density of primes starting with 1Density of integers with many prime factorsGrowth Rate of the Square-Free PartNumber of $k$-free integers of bounded radical













2












$begingroup$


It is well-known how to compute the density of square-free numbers, to get
$$ lim_{Ntoinfty} frac{#{ n leq N : n text{ square-free}}}{N} = frac{6}{pi^2}.$$



What is the density of numbers such that both $n$ and $n+1$ are square-free?
In other words, what is
$$lim_{Ntoinfty} frac{#{ n leq N : n(n+1) text{ square-free}}}{N} $$
(if the limit exists)?
I'm guessing this has been studied before. Does anyone have a textbook or paper reference?










share|cite|improve this question









$endgroup$










  • 1




    $begingroup$
    This question is essentially the same as mathoverflow.net/questions/177849/… See my answer there.
    $endgroup$
    – GH from MO
    7 hours ago






  • 1




    $begingroup$
    Also essentially a duplicate of MO 59741 <mathoverflow.net/questions/59741> which asked the same question about squarefree triples $(4a+1,4a+2,4a+3)$.
    $endgroup$
    – Noam D. Elkies
    6 hours ago
















2












$begingroup$


It is well-known how to compute the density of square-free numbers, to get
$$ lim_{Ntoinfty} frac{#{ n leq N : n text{ square-free}}}{N} = frac{6}{pi^2}.$$



What is the density of numbers such that both $n$ and $n+1$ are square-free?
In other words, what is
$$lim_{Ntoinfty} frac{#{ n leq N : n(n+1) text{ square-free}}}{N} $$
(if the limit exists)?
I'm guessing this has been studied before. Does anyone have a textbook or paper reference?










share|cite|improve this question









$endgroup$










  • 1




    $begingroup$
    This question is essentially the same as mathoverflow.net/questions/177849/… See my answer there.
    $endgroup$
    – GH from MO
    7 hours ago






  • 1




    $begingroup$
    Also essentially a duplicate of MO 59741 <mathoverflow.net/questions/59741> which asked the same question about squarefree triples $(4a+1,4a+2,4a+3)$.
    $endgroup$
    – Noam D. Elkies
    6 hours ago














2












2








2





$begingroup$


It is well-known how to compute the density of square-free numbers, to get
$$ lim_{Ntoinfty} frac{#{ n leq N : n text{ square-free}}}{N} = frac{6}{pi^2}.$$



What is the density of numbers such that both $n$ and $n+1$ are square-free?
In other words, what is
$$lim_{Ntoinfty} frac{#{ n leq N : n(n+1) text{ square-free}}}{N} $$
(if the limit exists)?
I'm guessing this has been studied before. Does anyone have a textbook or paper reference?










share|cite|improve this question









$endgroup$




It is well-known how to compute the density of square-free numbers, to get
$$ lim_{Ntoinfty} frac{#{ n leq N : n text{ square-free}}}{N} = frac{6}{pi^2}.$$



What is the density of numbers such that both $n$ and $n+1$ are square-free?
In other words, what is
$$lim_{Ntoinfty} frac{#{ n leq N : n(n+1) text{ square-free}}}{N} $$
(if the limit exists)?
I'm guessing this has been studied before. Does anyone have a textbook or paper reference?







nt.number-theory reference-request analytic-number-theory






share|cite|improve this question













share|cite|improve this question











share|cite|improve this question




share|cite|improve this question










asked 8 hours ago









Harry RichmanHarry Richman

9886 silver badges18 bronze badges




9886 silver badges18 bronze badges











  • 1




    $begingroup$
    This question is essentially the same as mathoverflow.net/questions/177849/… See my answer there.
    $endgroup$
    – GH from MO
    7 hours ago






  • 1




    $begingroup$
    Also essentially a duplicate of MO 59741 <mathoverflow.net/questions/59741> which asked the same question about squarefree triples $(4a+1,4a+2,4a+3)$.
    $endgroup$
    – Noam D. Elkies
    6 hours ago














  • 1




    $begingroup$
    This question is essentially the same as mathoverflow.net/questions/177849/… See my answer there.
    $endgroup$
    – GH from MO
    7 hours ago






  • 1




    $begingroup$
    Also essentially a duplicate of MO 59741 <mathoverflow.net/questions/59741> which asked the same question about squarefree triples $(4a+1,4a+2,4a+3)$.
    $endgroup$
    – Noam D. Elkies
    6 hours ago








1




1




$begingroup$
This question is essentially the same as mathoverflow.net/questions/177849/… See my answer there.
$endgroup$
– GH from MO
7 hours ago




$begingroup$
This question is essentially the same as mathoverflow.net/questions/177849/… See my answer there.
$endgroup$
– GH from MO
7 hours ago




1




1




$begingroup$
Also essentially a duplicate of MO 59741 <mathoverflow.net/questions/59741> which asked the same question about squarefree triples $(4a+1,4a+2,4a+3)$.
$endgroup$
– Noam D. Elkies
6 hours ago




$begingroup$
Also essentially a duplicate of MO 59741 <mathoverflow.net/questions/59741> which asked the same question about squarefree triples $(4a+1,4a+2,4a+3)$.
$endgroup$
– Noam D. Elkies
6 hours ago










1 Answer
1






active

oldest

votes


















5












$begingroup$

See NOTE ON AN ASYMPTOTIC FORMULA CONNECTED WITH r-FREE INTEGERS by
L. MIRSKY, The Quarterly Journal of Mathematics, Volume os-18, Issue 1, 1947, Pages 178–182, https://doi.org/10.1093/qmath/os-18.1.178



This paper is more general, i.e., for $r$ tuples of square free numbers with fixed gap sizes. The number of such integer pairs $leq x$ is given by
$$
Ax+O( x^{frac{2}{3}+epsilon}(log x)^{frac{4}{3}}),
$$

where $A$ is a constant. See also here where the constant $A$ is evaluated in terms of Euler products.






share|cite|improve this answer









$endgroup$


















    Your Answer








    StackExchange.ready(function() {
    var channelOptions = {
    tags: "".split(" "),
    id: "504"
    };
    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',
    autoActivateHeartbeat: false,
    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
    });


    }
    });














    draft saved

    draft discarded


















    StackExchange.ready(
    function () {
    StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmathoverflow.net%2fquestions%2f337444%2fdensity-of-twin-square-free-numbers%23new-answer', 'question_page');
    }
    );

    Post as a guest















    Required, but never shown

























    1 Answer
    1






    active

    oldest

    votes








    1 Answer
    1






    active

    oldest

    votes









    active

    oldest

    votes






    active

    oldest

    votes









    5












    $begingroup$

    See NOTE ON AN ASYMPTOTIC FORMULA CONNECTED WITH r-FREE INTEGERS by
    L. MIRSKY, The Quarterly Journal of Mathematics, Volume os-18, Issue 1, 1947, Pages 178–182, https://doi.org/10.1093/qmath/os-18.1.178



    This paper is more general, i.e., for $r$ tuples of square free numbers with fixed gap sizes. The number of such integer pairs $leq x$ is given by
    $$
    Ax+O( x^{frac{2}{3}+epsilon}(log x)^{frac{4}{3}}),
    $$

    where $A$ is a constant. See also here where the constant $A$ is evaluated in terms of Euler products.






    share|cite|improve this answer









    $endgroup$




















      5












      $begingroup$

      See NOTE ON AN ASYMPTOTIC FORMULA CONNECTED WITH r-FREE INTEGERS by
      L. MIRSKY, The Quarterly Journal of Mathematics, Volume os-18, Issue 1, 1947, Pages 178–182, https://doi.org/10.1093/qmath/os-18.1.178



      This paper is more general, i.e., for $r$ tuples of square free numbers with fixed gap sizes. The number of such integer pairs $leq x$ is given by
      $$
      Ax+O( x^{frac{2}{3}+epsilon}(log x)^{frac{4}{3}}),
      $$

      where $A$ is a constant. See also here where the constant $A$ is evaluated in terms of Euler products.






      share|cite|improve this answer









      $endgroup$


















        5












        5








        5





        $begingroup$

        See NOTE ON AN ASYMPTOTIC FORMULA CONNECTED WITH r-FREE INTEGERS by
        L. MIRSKY, The Quarterly Journal of Mathematics, Volume os-18, Issue 1, 1947, Pages 178–182, https://doi.org/10.1093/qmath/os-18.1.178



        This paper is more general, i.e., for $r$ tuples of square free numbers with fixed gap sizes. The number of such integer pairs $leq x$ is given by
        $$
        Ax+O( x^{frac{2}{3}+epsilon}(log x)^{frac{4}{3}}),
        $$

        where $A$ is a constant. See also here where the constant $A$ is evaluated in terms of Euler products.






        share|cite|improve this answer









        $endgroup$



        See NOTE ON AN ASYMPTOTIC FORMULA CONNECTED WITH r-FREE INTEGERS by
        L. MIRSKY, The Quarterly Journal of Mathematics, Volume os-18, Issue 1, 1947, Pages 178–182, https://doi.org/10.1093/qmath/os-18.1.178



        This paper is more general, i.e., for $r$ tuples of square free numbers with fixed gap sizes. The number of such integer pairs $leq x$ is given by
        $$
        Ax+O( x^{frac{2}{3}+epsilon}(log x)^{frac{4}{3}}),
        $$

        where $A$ is a constant. See also here where the constant $A$ is evaluated in terms of Euler products.







        share|cite|improve this answer












        share|cite|improve this answer



        share|cite|improve this answer










        answered 7 hours ago









        kodlukodlu

        4,5582 gold badges21 silver badges32 bronze badges




        4,5582 gold badges21 silver badges32 bronze badges

































            draft saved

            draft discarded




















































            Thanks for contributing an answer to MathOverflow!


            • Please be sure to answer the question. Provide details and share your research!

            But avoid



            • Asking for help, clarification, or responding to other answers.

            • Making statements based on opinion; back them up with references or personal experience.


            Use MathJax to format equations. MathJax reference.


            To learn more, see our tips on writing great answers.




            draft saved


            draft discarded














            StackExchange.ready(
            function () {
            StackExchange.openid.initPostLogin('.new-post-login', 'https%3a%2f%2fmathoverflow.net%2fquestions%2f337444%2fdensity-of-twin-square-free-numbers%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

            Taj Mahal Inhaltsverzeichnis Aufbau | Geschichte | 350-Jahr-Feier | Heutige Bedeutung | Siehe auch |...

            Baia Sprie Cuprins Etimologie | Istorie | Demografie | Politică și administrație | Arii naturale...

            Nicolae Petrescu-Găină Cuprins Biografie | Opera | In memoriam | Varia | Controverse, incertitudini...