id:A049198 - OEIS Search Results

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Not-square-free numbers whose Euler totient function is square-free.

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4, 9, 18, 49, 98, 121, 242, 529, 961, 1058, 1849, 1922, 2209, 3481, 3698, 4418, 4489, 5041, 6241, 6889, 6962, 8978, 10082, 10609, 11449, 12482, 13778, 17161, 19321, 21218, 22898, 27889, 32041, 34322, 36481, 38642, 44521, 49729, 51529, 55778 (list; graph; listen)

	OFFSET	`1,1`
	EXAMPLE	`a(27)=13778=28383 is divisible by a square, but Phi(13778)=6806=24183 is square-free.`
	MATHEMATICA	`Abs[ MoebiusMu[ EulerPhi[ x ] ] ]=1 and Abs[ MoebiusMu[ x ] ]=0`
	CROSSREFS	`A000010, A005117, A013929, A049199.` `Sequence in context: A083706 A074896 A015713 this_sequence A146303 A147977 A045278` `Adjacent sequences: A049195 A049196 A049197 this_sequence A049199 A049200 A049201`
	KEYWORD	`nonn,easy`
	AUTHOR	`Labos E. (labos(AT)ana.sote.hu)`

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Last modified December 3 22:15 EST 2009. Contains 170310 sequences.

AT&T Labs Research