Bash script:
#!/bin/bash
#sudo apt-get install djvulibre-bin imagemagick libtiff-tools
#rm *.tif
for (( i=0; i<=317; i++ ))
do ddjvu -page=$i -format=tiff assimil_france.djvu tmp$i.tif
convert tmp$i.tif -crop 50%x100% $i%d.tif
rm tmp$i.tif
done
for a in [0-9]*.tif; do
mv $a "printf %05d.%s ${a%.*} ${a##*.}"
done
tiffcp *.tif out.tif && tiff2pdf out.tif -j -o out.pdf && rm *.tif