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Search: id:A039698
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| A039698 |
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Numbers n such that phi(n) is of the form p-1 with p a prime number. |
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+0
4
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| 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 17, 18, 19, 21, 22, 23, 26, 27, 28, 29, 31, 32, 34, 36, 37, 38, 40, 41, 42, 43, 46, 47, 48, 49, 53, 54, 55, 57, 58, 59, 60, 61, 62, 63, 67, 71, 73, 74, 75, 76, 77, 79, 82, 83, 86, 88, 89, 91, 93, 94, 95, 97, 98, 99, 100, 101, 103
(list; graph; listen)
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OFFSET
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1,2
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COMMENT
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Positive integers n for which values of A039649(n) are primes. - Vladimir Shevelev (shevelev(AT)bgu.ac.il), May 10 2008
For every prime p, the numbers p and 2p are terms of this sequence. - Vladimir Shevelev (shevelev(AT)bgu.ac.il), May 10 2008
Union of A000040 and A066071. - Ray Chandler (rayjchandler(AT)sbcglobal.net), May 26 2008
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EXAMPLE
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phi(10)+1=4+1=5, a prime number.
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CROSSREFS
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Cf. A000010, A000040, A006093, A039649, A066071, A007614.
Sequence in context: A048326 A048339 A023783 this_sequence A078107 A072089 A072088
Adjacent sequences: A039695 A039696 A039697 this_sequence A039699 A039700 A039701
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KEYWORD
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nonn,easy
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AUTHOR
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Olivier Gerard (ogerard(AT)ext.jussieu.fr)
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EXTENSIONS
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Edited by njas, May 21 2008 at the suggestion of R. J. Mathar
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