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 A350299 Numbers k > 1 with sigma(k)/(k * log(log(k))) > sigma(m)/(m * log(log(m))) for all m > k, sigma(k) being A000203(k), the sum of the divisors of k. 1
 3, 4, 6, 12, 24, 60, 120, 180, 360, 2520, 5040 (list; graph; refs; listen; history; text; internal format)
 OFFSET 1,1 COMMENTS Gronwall's theorem says that lim sup_{k -> infinity} sigma(k)/(k*log(log(k))) = exp(gamma). Moreover if the Riemann hypothesis is true, we have sigma(k)/(k*log(log(k))) < exp(gamma) when k > 5040 (gamma = Euler-Mascheroni constant). The terms in the sequence listed above are provably correct since their ratios: sigma(k)/(k * log(log(k))) are greater than exp(gamma). REFERENCES Guy Robin, Grandes valeurs de la fonction somme des diviseurs et hypothèse de Riemann, J. Math. Pures Appl. 63 (1984), 187-213. LINKS Table of n, a(n) for n=1..11. Keith Briggs, Abundant numbers and the Riemann Hypothesis, Experimental Math., Vol. 16 (2006), pp. 251-256. S. Nazardonyavi and S. Yakubovich, Extremely Abundant Numbers and the Riemann Hypothesis, Journal of Integer Sequences, 17 (2014), Article 14.2.8. Thomas Strohmann, C++ code CROSSREFS Cf. A000203, A067698, A004394, A002093, A004490. Cf. also A001620, A073004. Sequence in context: A358358 A160684 A176045 * A255733 A137333 A006719 Adjacent sequences: A350296 A350297 A350298 * A350300 A350301 A350302 KEYWORD nonn AUTHOR Thomas Strohmann, Dec 23 2021 STATUS approved

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Last modified June 22 15:57 EDT 2024. Contains 373590 sequences. (Running on oeis4.)