On the Range of Arithmetic Means of the Fractional Parts of Harmonic Numbers

In this paper, the limit points of the sequence of arithmetic means <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mstyle scriptlevel="0" displaystyle="true"><mfrac><mn...

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Main Author: Artūras Dubickas
Format: Article
Language:English
Published: MDPI AG 2024-11-01
Series:Mathematics
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Online Access:https://www.mdpi.com/2227-7390/12/23/3731
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author Artūras Dubickas
author_facet Artūras Dubickas
author_sort Artūras Dubickas
collection DOAJ
description In this paper, the limit points of the sequence of arithmetic means <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mstyle scriptlevel="0" displaystyle="true"><mfrac><mn>1</mn><mi>n</mi></mfrac></mstyle><msubsup><mo>∑</mo><mrow><mi>m</mi><mo>=</mo><mn>1</mn></mrow><mi>n</mi></msubsup><msup><mrow><mo>{</mo><msub><mi>H</mi><mi>m</mi></msub><mo>}</mo></mrow><mi>σ</mi></msup></mrow></semantics></math></inline-formula> for <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>n</mi><mo>=</mo><mn>1</mn><mo>,</mo><mn>2</mn><mo>,</mo><mn>3</mn><mo>,</mo><mo>…</mo></mrow></semantics></math></inline-formula> are studied, where <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>H</mi><mi>m</mi></msub></semantics></math></inline-formula> is the <i>m</i>th harmonic number with fractional part <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>{</mo><msub><mi>H</mi><mi>m</mi></msub><mo>}</mo></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>σ</mi></semantics></math></inline-formula> is a fixed positive constant. In particular, for <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>σ</mi><mo>=</mo><mn>1</mn></mrow></semantics></math></inline-formula>, it is shown that the largest limit point of the above sequence is <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1</mn><mo>/</mo><mo>(</mo><mi>e</mi><mo>−</mo><mn>1</mn><mo>)</mo><mo>=</mo><mn>0.581976</mn><mo>…</mo></mrow></semantics></math></inline-formula>, its smallest limit point is <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1</mn><mo>−</mo><mo form="prefix">log</mo><mo>(</mo><mi>e</mi><mo>−</mo><mn>1</mn><mo>)</mo><mo>=</mo><mn>0.458675</mn><mo>…</mo></mrow></semantics></math></inline-formula>, and all limit points form a closed interval between these two constants. A similar result holds for the sequence <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mstyle scriptlevel="0" displaystyle="true"><mfrac><mn>1</mn><mi>n</mi></mfrac></mstyle><msubsup><mo>∑</mo><mrow><mi>m</mi><mo>=</mo><mn>1</mn></mrow><mi>n</mi></msubsup><mi>f</mi><mrow><mo>(</mo><mrow><mo>{</mo><msub><mi>H</mi><mi>m</mi></msub><mo>}</mo></mrow><mo>)</mo></mrow></mrow></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>n</mi><mo>=</mo><mn>1</mn><mo>,</mo><mn>2</mn><mo>,</mo><mn>3</mn><mo>,</mo><mo>…</mo></mrow></semantics></math></inline-formula>, where <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>f</mi><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow><mo>=</mo><msup><mi>x</mi><mi>σ</mi></msup></mrow></semantics></math></inline-formula> is replaced by an arbitrary absolutely continuous function <i>f</i> in <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>[</mo><mn>0</mn><mo>,</mo><mn>1</mn><mo>]</mo></mrow></semantics></math></inline-formula>.
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spelling doaj-art-7f8f39edee6e4177b2c4bf2b06c390422024-12-13T16:27:34ZengMDPI AGMathematics2227-73902024-11-011223373110.3390/math12233731On the Range of Arithmetic Means of the Fractional Parts of Harmonic NumbersArtūras Dubickas0Institute of Mathematics, Faculty of Mathematics and Informatics, Vilnius University, Naugarduko 24, LT-03225 Vilnius, LithuaniaIn this paper, the limit points of the sequence of arithmetic means <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mstyle scriptlevel="0" displaystyle="true"><mfrac><mn>1</mn><mi>n</mi></mfrac></mstyle><msubsup><mo>∑</mo><mrow><mi>m</mi><mo>=</mo><mn>1</mn></mrow><mi>n</mi></msubsup><msup><mrow><mo>{</mo><msub><mi>H</mi><mi>m</mi></msub><mo>}</mo></mrow><mi>σ</mi></msup></mrow></semantics></math></inline-formula> for <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>n</mi><mo>=</mo><mn>1</mn><mo>,</mo><mn>2</mn><mo>,</mo><mn>3</mn><mo>,</mo><mo>…</mo></mrow></semantics></math></inline-formula> are studied, where <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><msub><mi>H</mi><mi>m</mi></msub></semantics></math></inline-formula> is the <i>m</i>th harmonic number with fractional part <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>{</mo><msub><mi>H</mi><mi>m</mi></msub><mo>}</mo></mrow></semantics></math></inline-formula> and <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mi>σ</mi></semantics></math></inline-formula> is a fixed positive constant. In particular, for <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>σ</mi><mo>=</mo><mn>1</mn></mrow></semantics></math></inline-formula>, it is shown that the largest limit point of the above sequence is <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1</mn><mo>/</mo><mo>(</mo><mi>e</mi><mo>−</mo><mn>1</mn><mo>)</mo><mo>=</mo><mn>0.581976</mn><mo>…</mo></mrow></semantics></math></inline-formula>, its smallest limit point is <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mn>1</mn><mo>−</mo><mo form="prefix">log</mo><mo>(</mo><mi>e</mi><mo>−</mo><mn>1</mn><mo>)</mo><mo>=</mo><mn>0.458675</mn><mo>…</mo></mrow></semantics></math></inline-formula>, and all limit points form a closed interval between these two constants. A similar result holds for the sequence <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mstyle scriptlevel="0" displaystyle="true"><mfrac><mn>1</mn><mi>n</mi></mfrac></mstyle><msubsup><mo>∑</mo><mrow><mi>m</mi><mo>=</mo><mn>1</mn></mrow><mi>n</mi></msubsup><mi>f</mi><mrow><mo>(</mo><mrow><mo>{</mo><msub><mi>H</mi><mi>m</mi></msub><mo>}</mo></mrow><mo>)</mo></mrow></mrow></semantics></math></inline-formula>, <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>n</mi><mo>=</mo><mn>1</mn><mo>,</mo><mn>2</mn><mo>,</mo><mn>3</mn><mo>,</mo><mo>…</mo></mrow></semantics></math></inline-formula>, where <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mi>f</mi><mrow><mo>(</mo><mi>x</mi><mo>)</mo></mrow><mo>=</mo><msup><mi>x</mi><mi>σ</mi></msup></mrow></semantics></math></inline-formula> is replaced by an arbitrary absolutely continuous function <i>f</i> in <inline-formula><math xmlns="http://www.w3.org/1998/Math/MathML" display="inline"><semantics><mrow><mo>[</mo><mn>0</mn><mo>,</mo><mn>1</mn><mo>]</mo></mrow></semantics></math></inline-formula>.https://www.mdpi.com/2227-7390/12/23/3731harmonic numberfractional partarithmetic meanEuler’s constant
spellingShingle Artūras Dubickas
On the Range of Arithmetic Means of the Fractional Parts of Harmonic Numbers
Mathematics
harmonic number
fractional part
arithmetic mean
Euler’s constant
title On the Range of Arithmetic Means of the Fractional Parts of Harmonic Numbers
title_full On the Range of Arithmetic Means of the Fractional Parts of Harmonic Numbers
title_fullStr On the Range of Arithmetic Means of the Fractional Parts of Harmonic Numbers
title_full_unstemmed On the Range of Arithmetic Means of the Fractional Parts of Harmonic Numbers
title_short On the Range of Arithmetic Means of the Fractional Parts of Harmonic Numbers
title_sort on the range of arithmetic means of the fractional parts of harmonic numbers
topic harmonic number
fractional part
arithmetic mean
Euler’s constant
url https://www.mdpi.com/2227-7390/12/23/3731
work_keys_str_mv AT arturasdubickas ontherangeofarithmeticmeansofthefractionalpartsofharmonicnumbers