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A067800 Nonprime n such that phi(n) > n/2. 4
1, 9, 15, 21, 25, 27, 33, 35, 39, 45, 49, 51, 55, 57, 63, 65, 69, 75, 77, 81, 85, 87, 91, 93, 95, 99, 111, 115, 117, 119, 121, 123, 125, 129, 133, 135, 141, 143, 145, 147, 153, 155, 159, 161, 169, 171, 175, 177, 183, 185, 187, 189, 201, 203, 205, 207, 209, 213, 215 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Sequence is similar to A014076(n) giving odd nonprimes. Only 3 terms = 105, 165, 195 are not in the sequence among 59 terms < 210.

Cototient[m] > totient[m] equivalent to 2phi[m] < m; the missing terms mentioned here seem to form A036798. - Labos Elemer, May 08 2003

The number 9075 is not in this sequence, is in A014076 and is not in A036798, which means that the missing terms mentioned here do not form A036798 (cf. A118700). - R. J. Mathar, Aug 08 2007

LINKS

Table of n, a(n) for n=1..59.

CROSSREFS

Cf. A036798, A083254.

Sequence in context: A270574 A071904 A014076 * A155474 A100819 A046446

Adjacent sequences:  A067797 A067798 A067799 * A067801 A067802 A067803

KEYWORD

nonn

AUTHOR

Benoit Cloitre, Feb 07 2002

STATUS

approved

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Last modified April 25 16:08 EDT 2019. Contains 322461 sequences. (Running on oeis4.)