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On certain arithmetical products involving the divisors of an integer

József Sándor Notes on Number Theory and Discrete Mathematics Print ISSN 1310–5132, Online ISSN 2367–8275 Volume 30, 2024, Number 1, Pages 111–115 DOI: 10.7546/nntdm.2024.30.1.111-115 Full paper (PDF, 210 Kb) Details Authors and affiliations József Sándor Department of Mathematics, Babeș-Bolyai University … Continue reading →

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On Vandiver’s arithmetical function – II

József Sándor Notes on Number Theory and Discrete Mathematics Print ISSN 1310–5132, Online ISSN 2367–8275 Volume 28, 2022, Number 4, Pages 710–718 DOI: 10.7546/nntdm.2022.28.4.710-718 Full paper (PDF, 201 Kb) Details Authors and affiliations József Sándor Department of Mathematics, Babeş-Bolyai University … Continue reading →

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On Vandiver’s arithmetical function – I

József Sándor Notes on Number Theory and Discrete Mathematics Print ISSN 1310–5132, Online ISSN 2367–8275 Volume 27, 2021, Number 3, Pages 29–38 DOI: 10.7546/nntdm.2021.27.3.29-38 Full paper (PDF, 218 Kb) Details Authors and affiliations József Sándor Department of Mathematics, Babeş-Bolyai University … Continue reading →

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Inequalities for generalized divisor functions

József Sándor Notes on Number Theory and Discrete Mathematics Print ISSN 1310–5132, Online ISSN 2367–8275 Volume 27, 2021, Number 2, Pages 41–48 DOI: 10.7546/nntdm.2021.27.2.41-48 Full paper (PDF, 218 Kb) Details Authors and affiliations József Sándor Department of Mathematics, Babes-Bolyai University … Continue reading →

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A note on balanced numbers

József Sándor and Krassimir T. Atanassov Notes on Number Theory and Discrete Mathematics Print ISSN 1310–5132, Online ISSN 2367–8275 Volume 25, 2019, Number 4, Pages 8–15 DOI: 10.7546/nntdm.2019.25.4.8-15 Full paper (PDF, 198 Kb) Details Authors and affiliations József Sándor Department … Continue reading →

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Inequalities between the arithmetic functions φ, ψ and σ. Part 2

József Sándor and Krassimir Atanassov Notes on Number Theory and Discrete Mathematics Print ISSN 1310–5132, Online ISSN 2367–8275 Volume 25, 2019, Number 2, Pages 30–35 DOI: 10.7546/nntdm.2019.25.2.30-35 Full paper (PDF, 161 Kb) Details Authors and affiliations József Sándor Department of … Continue reading →

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On the Iyengar–Madhava Rao–Nanjundiah inequality and its hyperbolic version

József Sándor Notes on Number Theory and Discrete Mathematics Print ISSN 1310–5132, Online ISSN 2367–8275 Volume 24, 2018, Number 2, Pages 134–139 DOI: 10.7546/nntdm.2018.24.2.134-139 Full paper (PDF, 155 Kb) Download corrigendum: PDF, 275 Kb) Details Authors and affiliations József Sándor … Continue reading →

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Proofs of certain conjectures for means of two arguments

József Sándor Notes on Number Theory and Discrete Mathematics Print ISSN 1310–5132, Online ISSN 2367–8275 Volume 24, 2018, Number 1, Pages 43–48 DOI: 10.7546/nntdm.2018.24.1.43-48 Full paper (PDF, 150 Kb) Details Authors and affiliations József Sándor Department of Mathematics, Babeș-Bolyai University … Continue reading →

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Two applications of the Hadamard integral inequality

József Sándor Notes on Number Theory and Discrete Mathematics Print ISSN 1310–5132, Online ISSN 2367–8275 Volume 23, 2017, Number 4, Pages 52–55 Full paper (PDF, 133 Kb) Details Authors and affiliations József Sándor Department of Mathematics, Babeș-Bolyai University Cluj-Napoca, Romania … Continue reading →

Extensions of D’Aurizio’s trigonometric inequality

József Sándor Notes on Number Theory and Discrete Mathematics Print ISSN 1310–5132, Online ISSN 2367–8275 Volume 23, 2017, Number 2, Pages 81–83 Full paper (PDF, 141 Kb) Details Authors and affiliations József Sándor Babes-Bolyai University, Department of Mathematics Cluj-Napoca, Romania … Continue reading →