|
| |
|
|
A067224
|
|
Numbers n such that phi(5n-1) = sigma(n).
|
|
0
| |
|
|
5225, 20405, 181685, 210395, 302375, 302445, 524975, 1469555, 1563485, 1748855, 2791085, 3097055, 4418375, 4542065, 4735115, 5482235, 5567705, 5568615, 5683205, 5753405, 6457055, 7363013, 7531205, 8016435, 8043875, 9534185, 10511345, 10790325, 11504405
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,1
|
|
|
COMMENTS
| Are there any terms not congruent to 5 in the sequence?
a(22) = 7363013 is the first example. [Charles R Greathouse IV, Jan 29 2012]
|
|
|
PROG
| (PARI) for(n=1, 1e8, if(sigma(n)==eulerphi(5*n-1), print1(n", "))) \\ Charles R Greathouse IV, Jan 29 2012
|
|
|
CROSSREFS
| Sequence in context: A157511 A165599 A109159 * A204139 A093182 A179964
Adjacent sequences: A067221 A067222 A067223 * A067225 A067226 A067227
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Benoit Cloitre (benoit7848c(AT)orange.fr), Feb 20 2002
|
|
|
EXTENSIONS
| a(8)-a(29) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Jan 29 2012
|
| |
|
|
