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A066812
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a(n) is such that phi(a(n)+1)=phi(a(n)-1)
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3
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5, 8, 9, 11, 27, 33, 71, 75, 123, 147, 309, 315, 387, 513, 555, 573, 627, 636, 729, 795, 843, 911, 915, 1016, 1083, 1227, 1323, 1331, 1347, 1467, 1515, 1609, 1755, 1995, 2133, 2171, 2187, 2307, 2403, 2427, 2475, 2591, 2643, 2696, 2763, 2907, 3243, 3315
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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COMMENTS
| a(n) is even for n=2,18,24,44,67 while a(n) is odd for other values of n < 85.
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LINKS
| Harry J. Smith, Table of n, a(n) for n=1,...,1000
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FORMULA
| Conjecture : there is a constant 2 < c < 2.1 such that a(n)=n^c asymptotically.
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PROG
| (PARI) { n=0; a=1; for (m=1, 10^10, while (1, a++; if (eulerphi(a+1) == eulerphi(a-1), break)); write("b066812.txt", n++, " ", a); if (n==1000, return) ) } [From Harry J. Smith (hjsmithh(AT)sbcglobal.net), Mar 29 2010]
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CROSSREFS
| A001494(n) + 1.
Sequence in context: A165991 A191977 A101079 * A100832 A034812 A066467
Adjacent sequences: A066809 A066810 A066811 * A066813 A066814 A066815
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KEYWORD
| nonn
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AUTHOR
| Benoit Cloitre (benoit7848c(AT)orange.fr), Jan 20 2002
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EXTENSIONS
| Corrected by Ralf Stephan, Feb 20 2004
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