id:A060668 - OEIS Search Results

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Numbers n such that phi(x) = n has exactly 5 solutions.

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8, 20, 220, 272, 300, 368, 416, 456, 500, 656, 732, 848, 876, 1092, 1160, 1212, 1236, 1328, 1376, 1424, 1568, 1624, 1716, 1808, 2144, 2244, 2336, 2420, 2460, 2480, 2528, 2556, 2768, 3056, 3080, 3252, 3320, 3344, 3536, 3560, 3612, 3728, 3732, 3900, 4016 (list; graph; listen)

	OFFSET	`1,1`
	EXAMPLE	`8 = phi(15) = phi(16) = phi(20) = phi(24) = phi(30).`
	MATHEMATICA	`a = Table[ 0, {5000} ]; Do[ p = EulerPhi[ n ]; If[ p < 5001, a[[ p ]]++ ], {n, 1, 15000} ]; Select[ Range[ 5000 ], a[[ # ]] == 5 & ]`
	CROSSREFS	`Cf. A007366, A007367.` `Sequence in context: A014584 A074472 A094253 this_sequence A079386 A130021 A003864` `Adjacent sequences: A060665 A060666 A060667 this_sequence A060669 A060670 A060671`
	KEYWORD	`nonn`
	AUTHOR	`Robert G. Wilson v (rgwv(AT)rgwv.com), Apr 18 2001`

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Last modified December 2 15:58 EST 2008. Contains 150992 sequences.

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