|
|
A307115
|
|
Primitive 5-abundant numbers: Numbers k such that sigma(k) > 5k (A215264) all of whose proper divisors d are 5-deficient numbers (having sigma(d) < 5d).
|
|
2
|
|
|
122522400, 147026880, 183783600, 205405200, 220540320, 232792560, 273873600, 328648320, 428828400, 492972480, 497296800, 514594080, 537213600, 563603040, 575134560, 581981400, 605404800, 627026400, 629909280, 670269600, 684684000, 710629920, 739458720, 745945200
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,1
|
|
COMMENTS
|
Analogous to A071395 with abundancy index 5 instead of 2.
|
|
REFERENCES
|
Paul Erdős and János Surányi, Topics in the Theory of Numbers, New York: Springer, 2003, p. 243.
|
|
LINKS
|
|
|
MATHEMATICA
|
Select[Range@500000000, DivisorSigma[1, #] > 5 # && Times @@ Boole@ Map[DivisorSigma[1, #] < 5 # &, Most@ Divisors@ #] == 1 &] (* after Michael De Vlieger at A071395 *)
|
|
CROSSREFS
|
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
STATUS
|
approved
|
|
|
|