11+2+11+2+3+11+2+3+4+⋅⋅⋅+11+2+3+⋅⋅⋅⋅+19=？\frac{1}{1+2}+\frac{1}{1+2+3}+\frac{1}{1+2+3+4}+···+\frac{1}{1+2+3+····+19}=？1+21+1+2+31+1+2+3+41+⋅⋅⋅+1+2+3+⋅⋅⋅⋅+191=？
有啥简便方法嘛
