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A244723
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Nonprimes n such that, mu(n) = mu(phi(n)).
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1
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1, 8, 12, 14, 16, 20, 22, 24, 25, 27, 28, 32, 36, 40, 44, 45, 46, 48, 50, 52, 54, 56, 60, 63, 64, 68, 72, 75, 76, 80, 81, 84, 88, 90, 92, 94, 96, 99, 100, 104, 108, 112, 116, 117, 118, 120, 124, 125, 126, 128, 132, 135, 136, 140, 144, 147, 148, 150, 152, 153, 156, 160, 162, 164, 166
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OFFSET
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1,2
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COMMENTS
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Odd terms, with the exception of 1, are not squarefree. - Torlach Rush, Jul 22 2014.
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LINKS
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MAPLE
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filter:= proc(n) uses numtheory; not(isprime(n)) and mobius(n) = mobius(phi(n)) end proc;
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MATHEMATICA
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searchMax = 200; Complement[Select[Range[searchMax], MoebiusMu[#] == MoebiusMu[EulerPhi[#]] &], Prime[Range[PrimePi[searchMax]]]] (* Alonso del Arte, Jul 05 2014 *)
Select[Range[searchMax], !PrimeQ[#] && MoebiusMu[#] == MoebiusMu[EulerPhi[#]]& ] (* Zak Seidov, Jul 31 2014 *)
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PROG
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(PARI)
for(n=1, 10^3, if(!isprime(n)&&moebius(eulerphi(n))==moebius(n), print1(n, ", "))) \\ Derek Orr, Jul 30 2014
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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