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A049196 Square-free numbers whose Euler totient function is also square-free. +0
1
1, 2, 3, 6, 7, 11, 14, 22, 23, 31, 43, 46, 47, 59, 62, 67, 71, 79, 83, 86, 94, 103, 107, 118, 131, 134, 139, 142, 158, 166, 167, 179, 191, 206, 211, 214, 223, 227, 239, 262, 263, 278, 283, 311, 331, 334, 347, 358, 359, 367, 382, 383, 419, 422, 431, 439, 443, 446 (list; graph; listen)
OFFSET

1,2

EXAMPLE

86 is here because it is square-free and the same holds for Phi[ 86 ]=42.

MATHEMATICA

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

CROSSREFS

A000010, A005117, A013929.

Sequence in context: A008765 A018468 A117115 this_sequence A096578 A027754 A092857

Adjacent sequences: A049193 A049194 A049195 this_sequence A049197 A049198 A049199

KEYWORD

nonn

AUTHOR

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

page 1

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Last modified July 26 13:41 EDT 2008. Contains 142293 sequences.


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