A348847 Numbers k where the ratios A099378(k)/k reach a record value.

1, 2, 4, 8, 16, 36, 144, 576, 900, 3600, 14400, 32400, 129600, 435600, 6969600, 8643600, 34574400, 77792400, 311169600, 2498000400, 2800526400, 7779240000, 9992001600, 22482003600

Offset

1,2

Comments

Are there nonsquare terms in this sequence that are larger than 8?

Links

Table of n, a(n) for n=1..24.

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

Cf. A099377, A099378, A348414.

Sequence in context: A034343 A002876 A095236 * A018536 A337673 A162428

Adjacent sequences: A348844 A348845 A348846 * A348848 A348849 A348850

Keyword

nonn,more

Author

Amiram Eldar, Nov 02 2021

Status

approved