在熟知的组合恒等式Cn^m=Cn-1^m-1+Cn^m,1/Cn^m=m/m-1(1/Cn-1^m-1+Cn^m-1/Cn^m-1),1/Cn^m+1/Cn^m+1=n+1/n^Cn-1^m的基础上,利用复变函数与初等的方法,得出组合数倒数和的一组非常有趣的组合恒等式,即1/Cn^m+1/Cn+1^n+1/Cn+2^n+…+1/Cn+m-1^n=n/n-1(1-1/Cn+m-1^n-1),1/Cn^m-1/Cn^m+1+1/Cn^m+3+…+(-1)^k 1/Cn^m+k=n+1/n+2(1/Cn+1^m+(-1)^k 1/Cn+1^m+k+1)等。
The main purpose of this paper is using the combinations formula Cn^m=Cn-1^m-1+Cn^m,1/Cn^m=m/m-1(1/Cn-1^m-1+Cn^m-1/Cn^m-1),1/Cn^m+1/Cn^m+1=n+1/n^Cn-1^m ;complex analysis and the elementary method to study the combinatorial number, and give some new interesting combinatorial identities of combinatorial number reciprocal :1/Cn^m+1/Cn+1^n+1/Cn+2^n+…+1/Cn+m-1^n=n/n-1(1-1/Cn+m-1^n-1),1/Cn^m-1/Cn^m+1+1/Cn^m+3+…+(-1)^k 1/Cn^m+k=n+1/n+2(1/Cn+1^m+(-1)^k 1/Cn+1^m+k+1);