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In number theory, the von Staudt–Clausen theorem is a result determining the fractional part of Bernoulli numbers, found independently by and . Specifically, if ''n'' is a positive integer and we add 1/''p'' to the Bernoulli number ''B''2''n'' for every prime ''p'' such that ''p'' − 1 divides 2''n'', we obtain an integer, i.e., This fact immediately allows us to characterize the denominators of the non-zero Bernoulli numbers ''B''2''n'' as the product of all primes ''p'' such that ''p'' − 1 divides 2''n''; consequently the denominators are square-free and divisible by 6. These denominators are : 6, 30, 42, 30, 66, 2730, 6, 510, 798, 330, 138, 2730, 6, 870, 14322, 510, 6, 1919190, 6, 13530, ... . == Proof == A proof of the Von Staudt–Clausen theorem follows from an explicit formula for Bernoulli numbers which is: : and as a corollary: : where are the Stirling numbers of the second kind. Furthermore the following lemmas are needed: Let p be a prime number then, 1. If p-1 divides 2n then, : 2. If p-1 does not divide 2n then, : Proof of (1) and (2): One has from Fermat's little theorem, : for . If p-1 divides 2n then one has, : for . Thereafter one has, : If one lets (Greatest integer function) then after iteration one has, : for and 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「Von Staudt–Clausen theorem」の詳細全文を読む スポンサード リンク
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