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A073543
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Numbers n such that 1/(1/phi(n) + 1/phi(n+1) + 1/phi(n+2)) is an integer.
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0
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12, 36, 37, 72, 73, 86, 95, 181, 192, 482, 540, 541, 560, 637, 813, 1152, 1620, 1621, 1683, 2017, 2101, 2283, 2557, 2592, 2642, 2916, 3031, 3032, 3061, 3381, 3624, 3625, 4357, 5077, 5186, 5581, 6337, 6661, 7417, 8100, 9118, 9181, 9299, 9720, 9901
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,1
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EXAMPLE
| 1/phi(2283)+1/phi(2284)+1/phi(2285) = 1/1520+1/1140+1/1824 = 1/480 so 2283 is in the sequence.
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MATHEMATICA
| Select[Range[10000], IntegerQ[1/Sum[1/EulerPhi[ #+i], {i, 0, 2}]]&]
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CROSSREFS
| Sequence in context: A038006 A205967 A203378 * A074234 A076515 A039317
Adjacent sequences: A073540 A073541 A073542 * A073544 A073545 A073546
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KEYWORD
| easy,nonn
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AUTHOR
| Benoit Cloitre (benoit7848c(AT)orange.fr), Aug 27 2002
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EXTENSIONS
| Edited by Dean Hickerson (dean.hickerson(AT)yahoo.com), Sep 03 2002
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