翻訳と辞書 Words near each other ・ Arithmetic (song) ・ Arithmetic and geometric Frobenius ・ Arithmetic circuit complexity ・ Arithmetic coding ・ Arithmetic combinatorics ・ Arithmetic derivative ・ Arithmetic dynamics ・ Arithmetic for Parents ・ Arithmetic function ・ Arithmetic genus ・ Arithmetic group ・ Arithmetic hyperbolic 3-manifold ・ Arithmetic IF ・ Arithmetic logic unit ・ Arithmetic mean ・ Arithmetic number ・ Arithmetic of abelian varieties ・ Arithmetic overflow ・ Arithmetic progression ・ Arithmetic rope ・ Arithmetic shift ・ Arithmetic surface ・ Arithmetic topology ・ Arithmetic underflow ・ Arithmetic variety ・ Arithmetic zeta function ・ Arithmetica ・ Arithmetica Universalis ・ Arithmetical hierarchy ・ Arithmetical ring Dictionary Lists mini英和辞書 mini和英辞書 Webster 1913 Latin-English FOLDOC Wikipedia English ウィキペディア

翻訳と辞書　辞書検索 [ 開発暫定版 ] スポンサード リンク Arithmetic number ： ウィキペディア英語版 Arithmetic number In number theory, an arithmetic number is an integer for which the average of its positive divisors is also an integer. For instance, 6 is an arithmetic number because the average of its divisors is :$\backslash frac=3,$ which is also an integer. However, 2 is not an arithmetic number because its only divisors are 1 and 2, and their average 3/2 is not an integer. The first numbers in the sequence of arithmetic numbers are :1, 3, 5, 6, 7, 11, 13, 14, 15, 17, 19, 20, 21, 22, 23, 27, 29, 30, 31, 33, 35, 37, 38, 39, 41, 42, 43, 44, 45, 46, 47, 49, ... . ==Density== It is known that the natural density of such numbers is 1:〔Guy (2004) p.76〕 indeed, the proportion of numbers less than ''X'' which are not arithmetic is asymptotically :$\backslash exp\backslash left(\; \backslash right)$ where ''c'' = 2 √ log 2 + o(1). A number ''N'' is arithmetic if the number of divisors ''d''(''N'') divides the sum of divisors σ(''N''). It is known that the density of integers ''N'' obeying the stronger condition that ''d''(''N'')2 divides σ(''N'') is 1/2.〔〔 抄文引用元・出典: フリー百科事典『 ウィキペディア（Wikipedia）』 ■ウィキペディアで「Arithmetic number」の詳細全文を読む スポンサード リンク 翻訳と辞書 : 翻訳のためのインターネットリソース Copyright(C) kotoba.ne.jp 1997-2016. All Rights Reserved.