|
Search: id:A066177
|
|
|
| A066177 |
|
Numbers n such that sigma(n+1)-sigma(n) = -sigma(n)/d(n), where d(n) denotes the number of divisors of n. |
|
+0
1
|
|
| 165, 1106, 7006, 11516, 12597, 14882, 16604, 21045, 23541, 39866, 42465, 43172, 46078, 67198, 95588
(list; graph; listen)
|
|
|
OFFSET
|
1,1
|
|
|
COMMENT
|
These are the n at which the divisor sum, sigma(n), is decreasing at a rate equal to the average divisor size, sigma(n)/d(n).
|
|
EXAMPLE
|
sigma(165)-sigma(166) = 288-252 = 36 = 288/8 = sigma(165)/d(165).
|
|
MATHEMATICA
|
Select[ Range[ 1, 10^5 ], DivisorSigma[ 1, # ]-DivisorSigma[ 1, #+1 ]==DivisorSigma[ 1, # ]/DivisorSigma[ 0, # ] & ]
|
|
CROSSREFS
|
Sequence in context: A135806 A157090 A124409 this_sequence A027796 A145055 A105944
Adjacent sequences: A066174 A066175 A066176 this_sequence A066178 A066179 A066180
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Joseph L. Pe (joseph_l_pe(AT)hotmail.com), Dec 14 2001
|
|
|
Search completed in 0.002 seconds
|
