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Büchi's problem, also known as the ''n'' squares' problem, is an open problem from number theory named after the Swiss mathematician Julius Richard Büchi. It asks whether there is a positive integer ''M'' such that every sequence of ''M'' or more integer squares, whose second difference is constant and equal to 2, is necessarily a sequence of squares of the form (''x'' + ''i'')2, ''i'' = 1, 2, ..., ''M'',... for some integer ''x''. In 1983, Douglas Hensley observed that Büchi's problem is equivalent to the following: Does there exist a positive integer ''M'' such that, for all integers ''x'' and ''a'', the quantity (''x'' + ''n'')2 + ''a'' cannot be a square for more than ''M'' consecutive values of ''n'', unless ''a'' = 0? ==Statement of Büchi's problem== Büchi's problem can be stated in the following way: Does there exist a positive integer ''M'' such that the system of equations : has only solutions satisfying Since the first difference of the sequence is the sequence , the second difference of is : Therefore, the above system of equations is equivalent to the single equation : where the unknown is the sequence . 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「Büchi's problem」の詳細全文を読む スポンサード リンク
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