N个随机数之和的母函数的三段迭代法

Three Steps Iteration Method of Generating Function of Sum of N Random Numbers

通过三段迭代的方式构造出一类母函数.利用此方法,可以得到(1+x+x^2+x^3+x^4+x^5+x^6)~n的展开式中任一项的系数,最后用2个例子演示了如何利用三段迭法求出母函数和分布律.

By means of three steps iteration method, a class of generating functions has been con- structed. By this method, the coefficients of any item in the expansion of （ 1 ＋ x ＋ x^2 ＋ x^3 ＋x^4＋ x5 ＋x6） n can be obtained. Finally, two examples were given to show how to obtain the generating function and the distribution law by using the three steps iteration method.