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Search: id:A067800
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| A067800 |
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Composite n such that phi(n) > n/2. |
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+0
5
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| 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; listen)
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OFFSET
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1,2
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COMMENT
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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 E. (labos(AT)ana.sote.hu), 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 (mathar(AT)strw.leidenuniv.nl), Aug 08 2007
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CROSSREFS
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Cf. A036798, A083254.
Adjacent sequences: A067797 A067798 A067799 this_sequence A067801 A067802 A067803
Sequence in context: A039769 A071904 A014076 this_sequence A100819 A046446 A046350
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KEYWORD
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nonn
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AUTHOR
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Benoit Cloitre (benoit7848c(AT)orange.fr), Feb 07 2002
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