the combination 1-2-3-4-5-6 has a lexographic value of one,
then 1-2-3-4-5-7 a value of 2 and so on until you reach 44-45-46-47-48-49 with a value of 13,983,816.
It just puts order in all combinations.
And a formula can calculate this value in no time.
now let say we print out all 13,983,816...