Squares, Cubes and Prime numbers












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Suppose $p$ and $p^2+2$ are prime numbers, prove that $p^3+2$ is also a prime number. Actually I do not know what is the relationship among square numbers, cube numbers and prime numbers










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  • 3




    $begingroup$
    This is a trick problem. There's only one such possible prime $p$ so that $p^2+2$ is prime...
    $endgroup$
    – Thomas Andrews
    Jul 20 '14 at 17:34










  • $begingroup$
    @ThomasAndrews what do you mean ? $3$ and $7$ seem to be such primes
    $endgroup$
    – Gabriel Romon
    Jul 20 '14 at 17:36










  • $begingroup$
    Is $7^2+2$ prime? @G.T.R
    $endgroup$
    – Thomas Andrews
    Jul 20 '14 at 17:37










  • $begingroup$
    Oops, my bad @ThomasAndrews
    $endgroup$
    – Gabriel Romon
    Jul 20 '14 at 17:37










  • $begingroup$
    math.stackexchange.com/questions/269790/… and math.stackexchange.com/questions/234077/prime-p-with-p28-prime
    $endgroup$
    – lab bhattacharjee
    Jul 20 '14 at 17:53
















0












$begingroup$


Suppose $p$ and $p^2+2$ are prime numbers, prove that $p^3+2$ is also a prime number. Actually I do not know what is the relationship among square numbers, cube numbers and prime numbers










share|cite|improve this question









$endgroup$








  • 3




    $begingroup$
    This is a trick problem. There's only one such possible prime $p$ so that $p^2+2$ is prime...
    $endgroup$
    – Thomas Andrews
    Jul 20 '14 at 17:34










  • $begingroup$
    @ThomasAndrews what do you mean ? $3$ and $7$ seem to be such primes
    $endgroup$
    – Gabriel Romon
    Jul 20 '14 at 17:36










  • $begingroup$
    Is $7^2+2$ prime? @G.T.R
    $endgroup$
    – Thomas Andrews
    Jul 20 '14 at 17:37










  • $begingroup$
    Oops, my bad @ThomasAndrews
    $endgroup$
    – Gabriel Romon
    Jul 20 '14 at 17:37










  • $begingroup$
    math.stackexchange.com/questions/269790/… and math.stackexchange.com/questions/234077/prime-p-with-p28-prime
    $endgroup$
    – lab bhattacharjee
    Jul 20 '14 at 17:53














0












0








0





$begingroup$


Suppose $p$ and $p^2+2$ are prime numbers, prove that $p^3+2$ is also a prime number. Actually I do not know what is the relationship among square numbers, cube numbers and prime numbers










share|cite|improve this question









$endgroup$




Suppose $p$ and $p^2+2$ are prime numbers, prove that $p^3+2$ is also a prime number. Actually I do not know what is the relationship among square numbers, cube numbers and prime numbers







elementary-number-theory






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asked Jul 20 '14 at 17:30









Achari S GaneshaAchari S Ganesha

4441923




4441923








  • 3




    $begingroup$
    This is a trick problem. There's only one such possible prime $p$ so that $p^2+2$ is prime...
    $endgroup$
    – Thomas Andrews
    Jul 20 '14 at 17:34










  • $begingroup$
    @ThomasAndrews what do you mean ? $3$ and $7$ seem to be such primes
    $endgroup$
    – Gabriel Romon
    Jul 20 '14 at 17:36










  • $begingroup$
    Is $7^2+2$ prime? @G.T.R
    $endgroup$
    – Thomas Andrews
    Jul 20 '14 at 17:37










  • $begingroup$
    Oops, my bad @ThomasAndrews
    $endgroup$
    – Gabriel Romon
    Jul 20 '14 at 17:37










  • $begingroup$
    math.stackexchange.com/questions/269790/… and math.stackexchange.com/questions/234077/prime-p-with-p28-prime
    $endgroup$
    – lab bhattacharjee
    Jul 20 '14 at 17:53














  • 3




    $begingroup$
    This is a trick problem. There's only one such possible prime $p$ so that $p^2+2$ is prime...
    $endgroup$
    – Thomas Andrews
    Jul 20 '14 at 17:34










  • $begingroup$
    @ThomasAndrews what do you mean ? $3$ and $7$ seem to be such primes
    $endgroup$
    – Gabriel Romon
    Jul 20 '14 at 17:36










  • $begingroup$
    Is $7^2+2$ prime? @G.T.R
    $endgroup$
    – Thomas Andrews
    Jul 20 '14 at 17:37










  • $begingroup$
    Oops, my bad @ThomasAndrews
    $endgroup$
    – Gabriel Romon
    Jul 20 '14 at 17:37










  • $begingroup$
    math.stackexchange.com/questions/269790/… and math.stackexchange.com/questions/234077/prime-p-with-p28-prime
    $endgroup$
    – lab bhattacharjee
    Jul 20 '14 at 17:53








3




3




$begingroup$
This is a trick problem. There's only one such possible prime $p$ so that $p^2+2$ is prime...
$endgroup$
– Thomas Andrews
Jul 20 '14 at 17:34




$begingroup$
This is a trick problem. There's only one such possible prime $p$ so that $p^2+2$ is prime...
$endgroup$
– Thomas Andrews
Jul 20 '14 at 17:34












$begingroup$
@ThomasAndrews what do you mean ? $3$ and $7$ seem to be such primes
$endgroup$
– Gabriel Romon
Jul 20 '14 at 17:36




$begingroup$
@ThomasAndrews what do you mean ? $3$ and $7$ seem to be such primes
$endgroup$
– Gabriel Romon
Jul 20 '14 at 17:36












$begingroup$
Is $7^2+2$ prime? @G.T.R
$endgroup$
– Thomas Andrews
Jul 20 '14 at 17:37




$begingroup$
Is $7^2+2$ prime? @G.T.R
$endgroup$
– Thomas Andrews
Jul 20 '14 at 17:37












$begingroup$
Oops, my bad @ThomasAndrews
$endgroup$
– Gabriel Romon
Jul 20 '14 at 17:37




$begingroup$
Oops, my bad @ThomasAndrews
$endgroup$
– Gabriel Romon
Jul 20 '14 at 17:37












$begingroup$
math.stackexchange.com/questions/269790/… and math.stackexchange.com/questions/234077/prime-p-with-p28-prime
$endgroup$
– lab bhattacharjee
Jul 20 '14 at 17:53




$begingroup$
math.stackexchange.com/questions/269790/… and math.stackexchange.com/questions/234077/prime-p-with-p28-prime
$endgroup$
– lab bhattacharjee
Jul 20 '14 at 17:53










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$begingroup$

Hint: if $p equiv pm 1 mod 3$, then what is $p^2 + 2 mod 3$? How many primes $p$ are there such that $p^2 + 2$ is also prime?






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    $begingroup$

    Hint: if $p equiv pm 1 mod 3$, then what is $p^2 + 2 mod 3$? How many primes $p$ are there such that $p^2 + 2$ is also prime?






    share|cite|improve this answer









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      0












      $begingroup$

      Hint: if $p equiv pm 1 mod 3$, then what is $p^2 + 2 mod 3$? How many primes $p$ are there such that $p^2 + 2$ is also prime?






      share|cite|improve this answer









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        $begingroup$

        Hint: if $p equiv pm 1 mod 3$, then what is $p^2 + 2 mod 3$? How many primes $p$ are there such that $p^2 + 2$ is also prime?






        share|cite|improve this answer









        $endgroup$



        Hint: if $p equiv pm 1 mod 3$, then what is $p^2 + 2 mod 3$? How many primes $p$ are there such that $p^2 + 2$ is also prime?







        share|cite|improve this answer












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        answered Jul 20 '14 at 17:32









        Mathmo123Mathmo123

        17.8k33165




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