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A362414 a(n) = gcd(n, phi(n)^2) / gcd(n, phi(n)). 1

%I #18 Oct 22 2023 15:06:10

%S 1,1,1,2,1,1,1,2,3,1,1,1,1,1,1,2,1,3,1,1,1,1,1,1,5,1,3,1,1,1,1,2,1,1,

%T 1,3,1,1,1,1,1,1,1,1,3,1,1,1,7,5,1,1,1,3,1,1,1,1,1,1,1,1,1,2,1,1,1,1,

%U 1,1,1,3,1,1,5,1,1,1,1,1,3,1,1,1,1,1,1,1,1,3,1,1,1,1,1,1,1,7,3,5

%N a(n) = gcd(n, phi(n)^2) / gcd(n, phi(n)).

%C a(n) = 1 if n is squarefree.

%H Paolo Xausa, <a href="/A362414/b362414.txt">Table of n, a(n) for n = 1..10000</a>

%F a(n) = gcd(n,A127473(n)) / A009195(n).

%F 1 <= a(n) <= sqrt(n). The lower bound is sharp (squarefree numbers), as is the upper bound (squares of primes). - _Charles R Greathouse IV_, May 03 2023

%t A362414[n_]:=With[{p=EulerPhi[n]},GCD[n,p^2]/GCD[n,p]];

%t Array[A362414,100] (* _Paolo Xausa_, Oct 22 2023 *)

%o (Magma) [Gcd(n, EulerPhi(n)^2) / Gcd(n, EulerPhi(n)): n in [1..100]];

%o (PARI) a(n)=my(f=eulerphi(n)); gcd(n,f^2)/gcd(n,f) \\ _Charles R Greathouse IV_, May 03 2023

%Y Cf. A000010, A000188, A009195.

%K nonn,easy

%O 1,4

%A _Juri-Stepan Gerasimov_, Apr 19 2023

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Last modified August 27 12:59 EDT 2024. Contains 375469 sequences. (Running on oeis4.)