|
Search: id:A056550
|
|
|
| A056550 |
|
Numbers n such that Sum_{k=1..n} sigma(k) is divisible by n, where sigma(k) = sum of divisors of k (A000203). |
|
+0
2
|
|
| 1, 2, 8, 11, 17, 63, 180, 259, 818, 2161, 4441, 8305, 11998, 694218, 3447076, 4393603, 57402883, 73459800, 121475393, 2068420025, 5577330586, 13320495021, 35297649260, 138630178659
(list; graph; listen)
|
|
|
OFFSET
|
1,2
|
|
|
FORMULA
|
Values of n for which A024916(n)/n is integer.
|
|
MAPLE
|
f := []: for i from 1 to 9000 do if add(sigma(n), n=1..i) mod i = 0 then f := [op(f), i] fi; od; f;
|
|
CROSSREFS
|
Cf. A000203, A024916.
Sequence in context: A064105 A129516 A143189 this_sequence A074263 A009420 A090746
Adjacent sequences: A056547 A056548 A056549 this_sequence A056551 A056552 A056553
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
Asher Auel (asher.auel(AT)reed.edu) Jun 06 2000
|
|
EXTENSIONS
|
More terms from Jud McCranie (j.mccranie(AT)comcast.net), Jul 04 2000
a(19)-a(24) from Donovan Johnson (donovan.johnson(AT)yahoo.com), Dec 29 2008
|
|
|
Search completed in 0.002 seconds
|
