|
Search: id:A073543
|
|
|
| A073543 |
|
Numbers n such that 1/(1/phi(n) + 1/phi(n+1) + 1/phi(n+2)) is an integer. |
|
+0
1
|
|
| 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; listen)
|
|
|
OFFSET
|
1,1
|
|
|
EXAMPLE
|
1/phi(2283)+1/phi(2284)+1/phi(2285) = 1/1520+1/1140+1/1824 = 1/480 so 2283 is in the sequence.
|
|
MATHEMATICA
|
Select[Range[10000], IntegerQ[1/Sum[1/EulerPhi[ #+i], {i, 0, 2}]]&]
|
|
CROSSREFS
|
Sequence in context: A007794 A008653 A038006 this_sequence A074234 A076515 A039317
Adjacent sequences: A073540 A073541 A073542 this_sequence A073544 A073545 A073546
|
|
KEYWORD
|
easy,nonn
|
|
AUTHOR
|
Benoit Cloitre (benoit7848c(AT)orange.fr), Aug 27 2002
|
|
EXTENSIONS
|
Edited by Dean Hickerson (dean.hickerson(AT)yahoo.com), Sep 03 2002
|
|
|
Search completed in 0.002 seconds
|
