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A049197 Square-free numbers whose Euler totient function is not square-free. +0
1
5, 10, 13, 15, 17, 19, 21, 26, 29, 30, 33, 34, 35, 37, 38, 39, 41, 42, 51, 53, 55, 57, 58, 61, 65, 66, 69, 70, 73, 74, 77, 78, 82, 85, 87, 89, 91, 93, 95, 97, 101, 102, 105, 106, 109, 110, 111, 113, 114, 115, 119, 122, 123, 127, 129, 130, 133, 137, 138, 141, 143 (list; graph; listen)
OFFSET

1,1

EXAMPLE

110=2*5*11 is square-free but Phi[ 110 ]=40 is divisible by a square, so 110 is here.

MATHEMATICA

Abs[ MoebiusMu[ EulerPhi[ x ] ] ]=0 and Abs[ MoebiusMu[ x ] ]=1

CROSSREFS

A000010, A005117, A013929.

Sequence in context: A001974 A046130 A073503 this_sequence A009000 A057100 A009003

Adjacent sequences: A049194 A049195 A049196 this_sequence A049198 A049199 A049200

KEYWORD

nonn

AUTHOR

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

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Last modified December 17 23:40 EST 2009. Contains 171025 sequences.


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