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A066685
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Numbers n such that p(n) is congruent to EulerPhi(n) mod n, where p(n) denotes the n-th prime.
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0
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1, 2, 3, 789, 40087, 238717, 251737, 7847315, 69673727, 2283427137, 2664260621
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,2
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COMMENTS
| a(12) > 10^12. [From Donovan Johnson (donovan.johnson(AT)yahoo.com), Mar 14 2010]
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EXAMPLE
| p(1) = 2 is congruent to 0 mod 1, and EulerPhi(1) = 1 is congruent to 0 mod 1, so 1 is a term of the sequence.
p(3) = 5 is congruent to 2 mod 3, and EulerPhi(3) = 2 is congruent to 2 mod 3, so 3 is a term of the sequence.
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MATHEMATICA
| Select[ Range[ 1, 10^6 ], Mod[ EulerPhi[ # ], # ] == Mod[ Prime[ # ], # ] & ]
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CROSSREFS
| Sequence in context: A004887 A165770 A108332 * A076155 A136611 A004898
Adjacent sequences: A066682 A066683 A066684 * A066686 A066687 A066688
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KEYWORD
| nonn
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AUTHOR
| Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Jan 11 2002
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EXTENSIONS
| Examples revised by N. J. A. Sloane, Jan 31 2010
a(8)-a(11) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Mar 14 2010
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