|
| |
|
|
A097703
|
|
Numbers n such that m = 216n + 108 satisfies sigma(m) <> 2*usigma(m).
|
|
3
| |
|
|
1, 4, 7, 10, 12, 13, 16, 19, 22, 24, 25, 28, 31, 34, 37, 40, 43, 46, 49, 52, 55, 58, 60, 61, 62, 64, 67, 70, 73, 76, 79, 82, 84, 85, 87, 88, 91, 94, 97, 100, 103, 106, 109, 112, 115, 118, 121, 122, 124, 127, 130, 133, 136, 137, 139, 142, 144, 145, 148, 151, 154, 157
(list; graph; refs; listen; history; internal format)
|
|
|
|
OFFSET
| 1,2
|
|
|
COMMENTS
| Conjecture: all numbers of form 3k + 1 are here. Other terms are listed in A097704.
|
|
|
MATHEMATICA
| usigma[n_] := Block[{d = Divisors[n]}, Plus @@ Select[d, GCD[ #, n/# ] == 1 &]]; Complement[ Range[157], (Select[ Range[37000], DivisorSigma[1, # ] == 2usigma[ # ] &] - 108)/216] (from Robert G. Wilson v Aug 28 2004)
|
|
|
CROSSREFS
| Complement of A097702. Cf. A063880.
Sequence in context: A025357 A144020 A047845 * A104036 A178598 A176292
Adjacent sequences: A097700 A097701 A097702 * A097704 A097705 A097706
|
|
|
KEYWORD
| nonn
|
|
|
AUTHOR
| Ralf Stephan (ralf(AT)ark.in-berlin.de), Aug 26 2004
|
| |
|
|
