|
Search: id:A051948
|
|
|
| A051948 |
|
Numbers n such that n*sigma(n) == 2 mod phi(n). |
|
+0
2
|
|
| 2, 3, 4, 5, 6, 7, 11, 13, 17, 19, 22, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 127, 131, 137, 139, 149, 151, 157, 163, 167, 173, 179, 181, 191, 193, 197, 199, 211, 223, 227, 229, 233, 239, 241
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
REFERENCES
|
R. K. Guy, Unsolved Problems Number Theory, B37.
|
|
LINKS
|
Chris Nash, There no other solutions besides 4, 6, 22 and the primes (html, pdf).
C. Rivera, Puzzle 76
|
|
CROSSREFS
|
Cf. A002270.
Sequence in context: A090563 A045745 A054010 this_sequence A103539 A033086 A059768
Adjacent sequences: A051945 A051946 A051947 this_sequence A051949 A051950 A051951
|
|
KEYWORD
|
nonn,nice,easy
|
|
AUTHOR
|
N. J. A. Sloane (njas(AT)research.att.com), Dec 21 1999
|
|
|
Search completed in 0.002 seconds
|
