|
|
A182169
|
|
Numbers n such that sigma(n) divides sum_{k=1..n} tau(k), where tau(k) is the number of divisors of k (A000005) and sigma(n) is the sum of divisors of n (A000203).
|
|
0
|
|
|
1, 2, 7, 19, 358, 3845, 31138, 36461, 4286729, 81945545, 2059172170, 3071920146, 9331669953, 19026491086
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
|
|
LINKS
|
|
|
MATHEMATICA
|
Select[Range[1000000], Mod[Sum[DivisorSigma[0, n], {n, #}], DivisorSigma[1, #]] == 0 &] (* Jayanta Basu, Mar 28 2013 *)
|
|
PROG
|
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|