近年来,国内外数学竞赛中,常常出现含有特殊定义的问题,其题型有的要求写出符合定义的数(或数组)有多少个,有的要求写出符合定义的数(或数组)是什么.要解答这类问题的关键就在于深刻理解问题中的特殊概念,特殊定义的内含,并以此为依据,努力探索,准确推理.下面举例说明:例1 定义:如果 n 个不同的正整数,对其中任意两 In recent years, problems that contain special definitions often appear in mathematics competitions at home and abroad. Some questions require the number of numbers (or arrays) that meet the definition, and some require the number (or array) that matches the definition. What is it? The key to answering such questions is to deeply understand the special concepts in the questions, to include the special definitions, and to use them as a basis to diligently explore and accurately reason. The following example illustrates: Example 1 Definition: If n different a positive integer for any two of them