\begin{center}
\footnotesize
\setlength{\mylength}{\baselineskip}
\begin{longtable}{rp{0ex}p{9cm}p{0ex}RL}
\caption{Laurent polynomials and selected mutations for bucket 20.}\\

\toprule \multicolumn{1}{c}{{Node}}&& \multicolumn{1}{c}{{Laurent polynomial}} && \multicolumn{2}{c}{{Mutations from Figure~\ref{fig:20a}}} \\ \midrule \endfirsthead

\multicolumn{6}{c}{{\tablename\ \thetable{} -- continued from previous page}} \\ \addlinespace[1.7ex] \midrule \multicolumn{1}{c}{{Node}}&& \multicolumn{1}{c}{{Laurent polynomial}} && \multicolumn{2}{c}{{Mutations from Figure~\ref{fig:20a}}} \\ \midrule \endhead

\midrule \multicolumn{6}{c}{{Continued on next page}} \endfoot

\bottomrule \endlastfoot

124 && $x+\frac{x}{y}+\frac{2x}{yz}+\frac{x}{y^2z^2}+y+z+\frac{2}{yz}+\frac{1}{x}$ && $337 \colon {}$ & $\left(\frac{x(x+yz)}{yz},y,\frac{x+yz}{y}\right)$ \spacer \\* 
 &&  && $362 \colon {}$ & $\left(\frac{x(x+yz)}{yz},\frac{x+yz}{z},z\right)$ \spacer \\* 
 &&  && $496 \colon {}$ & $\left(\frac{(xyz+1)^2}{x^3y^2z^2},y,\frac{(xyz+1)^2}{x^2y^2z}\right)$ \spacer \\* 
 &&  && $581 \colon {}$ & $\left(\frac{(xyz+1)^2}{x^3y^2z^2},\frac{(xyz+1)^2}{x^2y^2z},y\right)$ \spacer \\* 
 &&  && $854 \colon {}$ & $\left(\frac{x^3yz^2}{x^2z^2+y(xz+1)^2},\frac{x^3z^2}{x^2z^2+y(xz+1)^2},\frac{x^2z^2+y(xz+1)^2}{x^2z}\right)$ \bottomspacer \\ \addlinespace[1.1ex]
 \rowcolor[gray]{0.95}
337 && $\frac{x^2}{yz}+\frac{x^2}{y^2z}+x+\frac{2x}{y}+\frac{2x}{yz}+y+z+\frac{1}{yz}+\frac{1}{x}$ && $124 \colon {}$ & $\left(\frac{xyz}{x+yz},y,\frac{yz^2}{x+yz}\right)$ \bottomspacer \\ \addlinespace[1.1ex]
 362 && $\frac{x^2}{yz}+x+\frac{x}{z}+\frac{x}{y}+\frac{2x}{yz}+y+z+\frac{1}{yz}+\frac{1}{x}$ && $124 \colon {}$ & $\left(\frac{xyz}{x+yz},z,\frac{y^2z}{x+yz}\right)$ \bottomspacer \\ \addlinespace[1.1ex]
 \rowcolor[gray]{0.95}
496 && $x+y+z+\frac{1}{x}+\frac{3}{xy}+\frac{2}{xyz}+\frac{2}{x^2yz}+\frac{3}{x^2y^2z}+\frac{1}{x^3y^2z^2}+\frac{1}{x^3y^3z^2}$ && $124 \colon {}$ & $\left(\frac{(x+yz)^2}{xy^2z^2},y,\frac{y^2z^3}{(x+yz)^2}\right)$ \bottomspacer \\ \addlinespace[1.1ex]
 581 && $x+y+z+\frac{1}{x}+\frac{1}{xz}+\frac{2}{xy}+\frac{2}{xyz}+\frac{2}{x^2yz}+\frac{1}{x^2y^2z}+\frac{1}{x^3y^2z^2}$ && $124 \colon {}$ & $\left(\frac{(x+yz)^2}{xy^2z^2},z,\frac{y^3z^2}{(x+yz)^2}\right)$ \spacer \\* 
 &&  && $2043 \colon {}$ & $\left(\frac{x^3z^2}{y+(xz+y)^2},\frac{y+(xz+y)^2}{x^2z},\frac{y+(xz+y)^2}{x^3yz^2}\right)$ \bottomspacer \\ \addlinespace[1.1ex]
 \rowcolor[gray]{0.95}
854 && $x+yz+y+z+\frac{2y}{x}+\frac{1}{x}+\frac{2}{xz}+\frac{1}{xy}+\frac{y}{x^2z}+\frac{2}{x^2z}+\frac{1}{x^3z^2}$ && $124 \colon {}$ & $\left(\frac{y^3z^2+x(yz+1)^2}{y^2z^2},\frac{x}{y},\frac{y^3z^3}{y^3z^2+x(yz+1)^2}\right)$ \bottomspacer \\ \addlinespace[1.1ex]
 2043 && $x+y+z+\frac{2y}{x}+\frac{2y}{xz}+\frac{1}{x}+\frac{2}{xz}+\frac{1}{xy}+\frac{y^2}{x^2z}+\frac{3y}{x^2z}+\frac{2}{x^2z}+\frac{y^2}{x^3z^2}+\frac{2y}{x^3z^2}+\frac{1}{x^3z^2}$ && $581 \colon {}$ & $\left(\frac{xz+(x^2yz+1)^2}{x^3y^2z^2},\frac{1}{xz},\frac{x^4y^3z^2}{xz+(x^2yz+1)^2}\right)$ \bottomspacer \\ \addlinespace[1.1ex]
 \end{longtable}
\end{center}
