|
| |
|
|
A273018
|
|
Ramanujan's largely composite numbers having 7 as the greatest prime divisor.
|
|
5
|
|
|
|
84, 168, 336, 420, 504, 630, 672, 840, 1260, 1680, 2520, 3360, 3780, 4200, 5040, 7560, 10080, 12600, 15120, 20160, 25200, 30240, 37800, 40320, 45360, 50400, 75600, 151200
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
|
OFFSET
|
1,1
|
|
|
COMMENTS
|
By the theorem in A273015, the sequence is finite.
|
|
|
LINKS
|
|
|
|
MATHEMATICA
|
a = {}; b = {0}; Do[If[# >= Max@ b, AppendTo[a, k] && AppendTo[b, #]] &@ DivisorSigma[0, k], {k, 10^7}]; Select[a, FactorInteger[#][[-1, 1]] == 7 &] (* Michael De Vlieger, May 13 2016 *)
|
|
|
CROSSREFS
|
|
|
|
KEYWORD
|
nonn,fini,full
|
|
|
AUTHOR
|
|
|
|
STATUS
|
approved
|
| |
|
|
