Creating a MySQL table to map integer ID #s to random #s (2 column table, 1 w/ sequential #s, and another unique non-repeating larger random #)

Basically want to end up with a table of numbers from 1-500,000 in one column (sequentially), and a set of random larger numbers (say from 10000000-99999999) and have none of these duplicated.

Will be basically used to obfuscate the first number, and used as a 'lookup table', as the 2nd number will be the public facing one.