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A049195 Euler totient function phi(n) is divisible by a square. +0
2
5, 8, 10, 12, 13, 15, 16, 17, 19, 20, 21, 24, 25, 26, 27, 28, 29, 30, 32, 33, 34, 35, 36, 37, 38, 39, 40, 41, 42, 44, 45, 48, 50, 51, 52, 53, 54, 55, 56, 57, 58, 60, 61, 63, 64, 65, 66, 68, 69, 70, 72, 73, 74, 75, 76, 77, 78, 80, 81, 82, 84, 85, 87, 88, 89, 90, 91, 92, 93, 95 (list; graph; listen)
OFFSET

1,1

EXAMPLE

72 and 73 belong because neither Phi[ 72 ]=24 nor Phi[ 73 ]=72 are square-free.

MATHEMATICA

Abs[ MoebiusMu[ EulerPhi[ x ] ] ]=0

CROSSREFS

A000010, A005117, A013929.

Sequence in context: A127493 A006186 A121901 this_sequence A064362 A115401 A065528

Adjacent sequences: A049192 A049193 A049194 this_sequence A049196 A049197 A049198

KEYWORD

nonn

AUTHOR

Labos E. (labos(AT)ana.sote.hu)

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Last modified July 25 07:41 EDT 2008. Contains 142293 sequences.


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