login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A348847 Numbers k where the ratios A099378(k)/k reach a record value. 0
1, 2, 4, 8, 16, 36, 144, 576, 900, 3600, 14400, 32400, 129600, 435600, 6969600, 8643600, 34574400, 77792400, 311169600, 2498000400, 2800526400, 7779240000, 9992001600, 22482003600 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Are there nonsquare terms in this sequence that are larger than 8?
LINKS
EXAMPLE
The first 4 ratios A099378(k)/k, for k = 1 to 4, are 1, 3/2, 2/3 and 7/4. The record values occur at k = 1, 2 and 4, the first 3 terms of this sequence.
MATHEMATICA
r[n_] := Denominator[DivisorSigma[0, n]/DivisorSigma[-1, n]]/n; s = {}; rm = 0; Do[If[(r1 = r[n]) > rm, rm = r1; AppendTo[s, n]], {n, 1, 5*10^5}]; s
CROSSREFS
Sequence in context: A034343 A002876 A095236 * A018536 A337673 A162428
KEYWORD
nonn,more
AUTHOR
Amiram Eldar, Nov 02 2021
STATUS
approved

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified July 21 20:59 EDT 2024. Contains 374475 sequences. (Running on oeis4.)