With curl:

  curl -O 'http://jacquesricher.com/NEETS/[14173-14196].pdf'

Here's a way to do 4 downloads in parallel:

  for ((i=14173; i<14197; i++)); do
    echo http://jacquesricher.com/NEETS/$i.pdf
  done | xargs -n 1 -P 4 curl -O

Another trick for parallel execution is to generate a makefile then use make -j.