\[d_{n}=\frac{\sum_{j=0}^{n}(-1)^{j}\genfrac{(}{)}{0.0pt}{}{n}{j}(j+1)^{n-1}%
\frac{s_{j}}{a_{j+1}}}{\sum_{j=0}^{n}(-1)^{j}\genfrac{(}{)}{0.0pt}{}{n}{j}(j+1%
)^{n-1}\frac{1}{a_{j+1}}}.\]