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A066071 Nonprime numbers n such that Phi[n] + 1 is prime. +0
13
1, 4, 6, 8, 9, 10, 12, 14, 18, 21, 22, 26, 27, 28, 32, 34, 36, 38, 40, 42, 46, 48, 49, 54, 55, 57, 58, 60, 62, 63, 74, 75, 76, 77, 82, 86, 88, 91, 93, 94, 95, 98, 99, 100, 106, 108, 110, 111, 114, 115, 117, 118, 119, 122, 124, 125, 126, 132, 133, 134, 135, 142, 145, 146 (list; graph; listen)
OFFSET

1,2

COMMENT

A039698 with the primes removed. For every prime p, 2p is in the sequence. - Ray Chandler (rayjchandler(AT)sbcglobal.net), May 26 2008

EXAMPLE

Solutions to 1+Phi[x]=13 are {13, 21, 26, 28, 36, 42} of which the 5 composites are in the sequence.

CROSSREFS

Cf. A000010, A000040, A006093, A039649, A039698, A066071-A066080.

Sequence in context: A070810 A129930 A109289 this_sequence A067013 A071070 A047820

Adjacent sequences: A066068 A066069 A066070 this_sequence A066072 A066073 A066074

KEYWORD

nonn

AUTHOR

Labos E. (labos(AT)ana.sote.hu), Dec 03 2001

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Last modified July 25 07:41 EDT 2008. Contains 142293 sequences.


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