ls *[25-50].fits
ls mjk00[25-50].fits
ls mjk[0025-0050]*
ls *[0025-0050]*

ls mjk00{25..50}.fits

ls mjk0{000..149}.fits

ls mjk002[56789].fits mjk00[34]?.fits

ls | sort -n | grep -E 'mjk00([2][5-9]|[3-4][0-9]|[5][0]).fits'

for i in $(seq 25 50 1) ; do ls --escape $(printf "mjk%04d*" $i) ||true; done

ls --escape mjk{0025..0050..1}* ||true