|
| |
|
|
A046841
|
|
Sum of divisors divides sum of cubes of divisors.
|
|
3
|
|
|
|
1, 2, 3, 5, 6, 7, 8, 10, 11, 12, 13, 14, 15, 16, 17, 19, 20, 21, 22, 23, 24, 26, 27, 29, 30, 31, 33, 34, 35, 37, 38, 39, 40, 41, 42, 43, 46, 47, 48, 51, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,2
|
|
|
COMMENTS
|
|
|
|
LINKS
|
|
|
|
EXAMPLE
|
2 is a term because 1+8 = 9 is divisible by 1+2 = 3.
x=208 is a term: The power sums of divisors for k=0,1,2,3 are as follows: 10,434,54970,10288838; and sigma(1,208)=434 divides sigma(3,208)=10288838=434*23707.
|
|
|
MAPLE
|
with(numtheory);
List046841:=proc(q) local a, b, k, n;
for n from 1 to q do
a:=divisors(n); b:=add(a[k]^3, k=1..nops(a));
if type(b/sigma(n), integer) then print(n); fi;
od; end:
|
|
|
MATHEMATICA
|
Select[Range@ 85, Divisible[DivisorSigma[3, #], DivisorSigma[1, #]] &] (* Michael De Vlieger, Aug 01 2017 *)
|
|
|
PROG
|
|
|
|
CROSSREFS
|
|
|
|
KEYWORD
|
nonn
|
|
|
AUTHOR
|
|
|
|
STATUS
|
approved
|
| |
|
|
