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A058652 Squarefree n such that sigma(phi(n)) = phi(sigma(n)). 1

%I #9 Mar 03 2013 08:53:34

%S 1,29262,114630,160986,179562,252978,502878,528954,780258,908070,

%T 1080906,1826454,2460786,2870142,3934686,5086722,5493030,6001206,

%U 6183078,6621270,6668634,8808234,9298110,9752190,10479282,11707518,12263334,12928254,13513278

%N Squarefree n such that sigma(phi(n)) = phi(sigma(n)).

%H Donovan Johnson, <a href="/A058652/b058652.txt">Table of n, a(n) for n = 1..500</a>

%t Select[ Range[ 10^7 ], DivisorSigma[ 1, EulerPhi[ # ] ] == EulerPhi[ DivisorSigma[ 1, # ] ] && Union[ Transpose[ FactorInteger[ # ] ] [ [ 2 ] ] ] == {1} & ]

%Y Cf. A033632.

%K nonn

%O 1,2

%A _Robert G. Wilson v_, Dec 26 2000

%E Prepended missing a(1)=1, _Donovan Johnson_, Mar 03 2012.

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Last modified May 11 17:33 EDT 2024. Contains 372410 sequences. (Running on oeis4.)