Similar to Lehmar's totient problem

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Find all positive integer such that
$$phi(n)^2mid n^2-1$$



My progress so far:



I proved that $n$ has to be a odd square-free integer. So $n=p_1p_2ldots p_k$. So the question can be restated as following:
$$prod (p_i-1)^2mid (p_1p_2ldots p_k)^2-1$$
From here I farther transformed the question as follows (Not sure if this simplifies the problem but it is definitely beautiful):



If $P(x)$ a polynomial such that all it's roots are distinct odd primes, prove that
$$P(1)^2nmid P(0)^2-1$$



And now I am stuck. Any help is appreciated.










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  • $n=1,2,3$ are solutions and there is no additional solution upto $n=10^8$
    – Peter
    Sep 9 at 21:57










  • Still no additional solution upto $n=10^9$
    – Peter
    Sep 9 at 22:44














up vote
2
down vote

favorite












Find all positive integer such that
$$phi(n)^2mid n^2-1$$



My progress so far:



I proved that $n$ has to be a odd square-free integer. So $n=p_1p_2ldots p_k$. So the question can be restated as following:
$$prod (p_i-1)^2mid (p_1p_2ldots p_k)^2-1$$
From here I farther transformed the question as follows (Not sure if this simplifies the problem but it is definitely beautiful):



If $P(x)$ a polynomial such that all it's roots are distinct odd primes, prove that
$$P(1)^2nmid P(0)^2-1$$



And now I am stuck. Any help is appreciated.










share|cite|improve this question





















  • $n=1,2,3$ are solutions and there is no additional solution upto $n=10^8$
    – Peter
    Sep 9 at 21:57










  • Still no additional solution upto $n=10^9$
    – Peter
    Sep 9 at 22:44












up vote
2
down vote

favorite









up vote
2
down vote

favorite











Find all positive integer such that
$$phi(n)^2mid n^2-1$$



My progress so far:



I proved that $n$ has to be a odd square-free integer. So $n=p_1p_2ldots p_k$. So the question can be restated as following:
$$prod (p_i-1)^2mid (p_1p_2ldots p_k)^2-1$$
From here I farther transformed the question as follows (Not sure if this simplifies the problem but it is definitely beautiful):



If $P(x)$ a polynomial such that all it's roots are distinct odd primes, prove that
$$P(1)^2nmid P(0)^2-1$$



And now I am stuck. Any help is appreciated.










share|cite|improve this question













Find all positive integer such that
$$phi(n)^2mid n^2-1$$



My progress so far:



I proved that $n$ has to be a odd square-free integer. So $n=p_1p_2ldots p_k$. So the question can be restated as following:
$$prod (p_i-1)^2mid (p_1p_2ldots p_k)^2-1$$
From here I farther transformed the question as follows (Not sure if this simplifies the problem but it is definitely beautiful):



If $P(x)$ a polynomial such that all it's roots are distinct odd primes, prove that
$$P(1)^2nmid P(0)^2-1$$



And now I am stuck. Any help is appreciated.







number-theory divisibility totient-function






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asked Sep 8 at 10:27









Basudeb Bhowmick

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  • $n=1,2,3$ are solutions and there is no additional solution upto $n=10^8$
    – Peter
    Sep 9 at 21:57










  • Still no additional solution upto $n=10^9$
    – Peter
    Sep 9 at 22:44
















  • $n=1,2,3$ are solutions and there is no additional solution upto $n=10^8$
    – Peter
    Sep 9 at 21:57










  • Still no additional solution upto $n=10^9$
    – Peter
    Sep 9 at 22:44















$n=1,2,3$ are solutions and there is no additional solution upto $n=10^8$
– Peter
Sep 9 at 21:57




$n=1,2,3$ are solutions and there is no additional solution upto $n=10^8$
– Peter
Sep 9 at 21:57












Still no additional solution upto $n=10^9$
– Peter
Sep 9 at 22:44




Still no additional solution upto $n=10^9$
– Peter
Sep 9 at 22:44















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