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 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 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

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