id:A049149 - OEIS Search Results

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Numbers n such that the Euler totient function phi(n) is square-free.

+0
2

1, 2, 3, 4, 6, 7, 9, 11, 14, 18, 22, 23, 31, 43, 46, 47, 49, 59, 62, 67, 71, 79, 83, 86, 94, 98, 103, 107, 118, 121, 131, 134, 139, 142, 158, 166, 167, 179, 191, 206, 211, 214, 223, 227, 239, 242, 262, 263, 278, 283, 311, 331, 334, 347, 358, 359, 367, 382, 383 (list; graph; listen)

	OFFSET	`1,2`
	EXAMPLE	`a(17)=49 is here because Phi(49)=42=237 is square-free. Primes p, such that p-1 is square-free are included.`
	MATHEMATICA	`Abs[ MoebiusMu[ EulerPhi[ x ] ] ]=1`
	CROSSREFS	`Cf. A000010, A005117, A013929.` `Sequence in context: A015851 A065156 A097987 this_sequence A156287 A162293 A145803` `Adjacent sequences: A049146 A049147 A049148 this_sequence A049150 A049151 A049152`
	KEYWORD	`nonn`
	AUTHOR	`Labos E. (labos(AT)ana.sote.hu)`
	EXTENSIONS	`Corrected by T. D. Noe (noe(AT)sspectra.com), Oct 25 2006`

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Last modified November 29 12:46 EST 2009. Contains 167659 sequences.

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