在中学范围内有相当数量的数列问题是属于高阶等差数列(特别是二阶等差数列)的求和问题。本文想在这方面从理论上和方法上作一个初步介绍。我们先从一个简单的数列:1~2,2~2,3~2,…,n~2,… (1)谈起,对此数列,若从第二项起用后项减去前项,便得到一个新的数列:2~2-1~2,3~2-2~2,4~2-3~2,…,n~2-(n-1)~2,… In the secondary school, there are a considerable number of series problems that belong to the summation problem of higher-order arithmetic series (especially second-order arithmetic series). This article wants to make a preliminary introduction in theory and method. Let’s start with a simple sequence: 1~2,2~2,3~2,...,n~2,... (1). For this series, if the previous term is subtracted from the second term, You get a new series: 2~2-1~2,3~2-2~2,4~2-3~2,...,n~2-(n-1)~2,...