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A217301 Numbers n such that gcd(n, phi(n)) = gcd(phi(n), sigma(n)) = gcd(sigma(n), n) = tau(n). 2
1, 184, 376, 1336, 1912, 2104, 2872, 3064, 3832, 4024, 4792, 5176, 5752, 5944, 6712, 6904, 7096, 7864, 8824, 9784, 10552, 10936, 11512, 11896, 12472, 12664, 12856, 14584, 14776, 16312, 16504, 16696, 17656, 19192, 19384, 19576, 20344, 21304, 21496, 22644 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 1..1000

MATHEMATICA

Select[Range[20000], GCD[#, EulerPhi[#]] ==  GCD[EulerPhi[#], DivisorSigma[1, #]] == GCD[#, DivisorSigma[1, #]] == DivisorSigma[0, #] &] (* Jean-Fran├žois Alcover, Mar 18 2013 *)

CROSSREFS

Cf. A069810.

Sequence in context: A171563 A347504 A061657 * A239457 A235258 A235251

Adjacent sequences:  A217298 A217299 A217300 * A217302 A217303 A217304

KEYWORD

nonn,easy

AUTHOR

Jayanta Basu, Mar 17 2013

STATUS

approved

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Last modified September 20 20:03 EDT 2021. Contains 347589 sequences. (Running on oeis4.)