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A060669 phi(x) = n has exactly 6 solutions. 0
12, 16, 84, 88, 112, 232, 348, 408, 592, 736, 760, 780, 832, 952, 984, 1032, 1048, 1068, 1128, 1232, 1272, 1312, 1332, 1428, 1432, 1488, 1552, 1608, 1692, 1912, 2052, 2200, 2272, 2292, 2436, 2484, 2552, 2576, 2608, 2632, 2700, 2728, 2832, 2848, 3048 (list; graph; refs; listen; history; internal format)
OFFSET

1,1

EXAMPLE

12 = phi(13) = phi(21) = phi(26) = phi(28) = phi(36) = phi(42).

MATHEMATICA

a = Table[ 0, {4000} ]; Do[ p = EulerPhi[ n ]; If[ p < 4001, a[ [ p ] ]++ ], {n, 1, 15000} ]; Select[ Range[ 4000 ], a[ [ # ] ] == 6 & ]

CROSSREFS

Cf. A007366, A007367.

Sequence in context: A058203 A050585 A050555 * A166644 A087657 A059390

Adjacent sequences:  A060666 A060667 A060668 * A060670 A060671 A060672

KEYWORD

nonn

AUTHOR

Robert G. Wilson v (rgwv(AT)rgwv.com), Apr 18 2001

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Last modified February 15 20:03 EST 2012. Contains 205852 sequences.