shell脚本，如何破解字符串对应的md5sum前的RANDOM对应数字？

已知下面的字符串是通过RANDOM随机数变量md5sum|cut-c 1-8截取后的结果，请破解这些字符串对应的md5sum前的RANDOM对应数字？
[root@localhost md5]# cat zifuchuang 
21029299
00205d1c
a3da1677
1f6d12dd
890684b
[root@localhost md5]# cat shuzi.sh 
#!/bin/bash

for i in `seq 1  65535`
do

     a=`echo $i|md5sum|cut -c 1-8`
     echo $i $a >> caihong.db

done
[root@localhost md5]# bash shuzi.sh 
[root@localhost md5]# ls
caihong.db  file  random2.sh  random3.sh  random4.sh  random.sh  shuzi.sh  suijishu  zifuchuang
[root@localhost md5]# grep 21029299 caihong.db 
25667 21029299
[root@localhost md5]# grep a3da1677 caihong.db 
25345 a3da1677
[root@localhost md5]# grep  1f6d12dd  caihong.db 
7041 1f6d12dd
[root@localhost md5]# grep  890684b  caihong.db 
10082 890684ba
[root@localhost md5]# grep  00205d1c  caihong.db 
1346 00205d1c
[root@localhost md5]# grep 890684b  caihong.db 
10082 890684ba
[root@localhost md5]# vi zifuchuang 
[root@localhost md5]#