Density of twin square-free numbersare 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

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













3












$begingroup$


It is well-known how to compute the density of square-free numbers, to get
$$ lim_Ntoinfty frac# n leq N : n text square-freeN = frac6pi^2.$$



What is the density of numbers such that both $n$ and $n+1$ are square-free?
In other words, what is
$$lim_Ntoinfty frac# n leq N : n(n+1) text square-freeN $$
(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
    7 hours ago















3












$begingroup$


It is well-known how to compute the density of square-free numbers, to get
$$ lim_Ntoinfty frac# n leq N : n text square-freeN = frac6pi^2.$$



What is the density of numbers such that both $n$ and $n+1$ are square-free?
In other words, what is
$$lim_Ntoinfty frac# n leq N : n(n+1) text square-freeN $$
(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
    7 hours ago













3












3








3





$begingroup$


It is well-known how to compute the density of square-free numbers, to get
$$ lim_Ntoinfty frac# n leq N : n text square-freeN = frac6pi^2.$$



What is the density of numbers such that both $n$ and $n+1$ are square-free?
In other words, what is
$$lim_Ntoinfty frac# n leq N : n(n+1) text square-freeN $$
(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
$$ lim_Ntoinfty frac# n leq N : n text square-freeN = frac6pi^2.$$



What is the density of numbers such that both $n$ and $n+1$ are square-free?
In other words, what is
$$lim_Ntoinfty frac# n leq N : n(n+1) text square-freeN $$
(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











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asked 8 hours ago









Harry RichmanHarry Richman

9936 silver badges18 bronze badges




9936 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
    7 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
    7 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
7 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
7 hours ago










1 Answer
1






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oldest

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6












$begingroup$

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
$$
Ax+O( x^frac23+epsilon(log x)^frac43),
$$

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






share|cite|improve this answer









$endgroup$

















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    1 Answer
    1






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    6












    $begingroup$

    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
    $$
    Ax+O( x^frac23+epsilon(log x)^frac43),
    $$

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






    share|cite|improve this answer









    $endgroup$



















      6












      $begingroup$

      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
      $$
      Ax+O( x^frac23+epsilon(log x)^frac43),
      $$

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






      share|cite|improve this answer









      $endgroup$

















        6












        6








        6





        $begingroup$

        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
        $$
        Ax+O( x^frac23+epsilon(log x)^frac43),
        $$

        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
        $$
        Ax+O( x^frac23+epsilon(log x)^frac43),
        $$

        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 8 hours ago









        kodlukodlu

        4,5682 gold badges21 silver badges32 bronze badges




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