|
|
A119239
|
|
Oddly superabundant numbers: odd n with sigma(n)/n > sigma(k)/k for all odd k < n.
|
|
4
|
|
|
1, 3, 9, 15, 45, 105, 315, 945, 1575, 2835, 3465, 10395, 17325, 31185, 45045, 135135, 225225, 405405, 675675, 2027025, 2297295, 3828825, 6891885, 11486475, 34459425, 43648605, 72747675, 130945815, 218243025, 654729075, 1003917915, 1527701175
(list;
graph;
refs;
listen;
history;
text;
internal format)
|
|
|
OFFSET
|
1,2
|
|
COMMENTS
|
Every oddly colossally abundant number (A110464) is in this sequence.
|
|
LINKS
|
|
|
MATHEMATICA
|
rec=0; lst={}; Do[abun=DivisorSigma[1, n]/n; If[abun>rec, rec=abun; AppendTo[lst, n]], {n, 1, 10^6, 2}]; lst
|
|
PROG
|
(PARI) r=0; forstep(n=1, 1e6, 2, t=sigma(n)/n; if(t>r, r=t; print1(n", "))) \\ Charles R Greathouse IV, Nov 27 2013
|
|
CROSSREFS
|
Cf. A004394 (superabundant numbers), A005231 (odd abundant numbers), A053624 (highly composite odd numbers).
|
|
KEYWORD
|
nonn
|
|
AUTHOR
|
|
|
EXTENSIONS
|
|
|
STATUS
|
approved
|
|
|
|