In ordinary mathematical progression, there would be no correlation. However, there may be an answer if we use Roman numerals:
6, 5, 15, 10, 70 . . ..
VI, V, XV, X, XXXC, XXCX, XCXX, CXXX, XXCM . . ..
Rocmike lucky you can google because you don't have the intelligence to answer the question if you couldn't.
XXXC is not a proper Roman numeral. 70 should be LXX, and the next number could be LX = 60.
Re-consider Augustian numerals. Perhaps you refer to Caesarian numerals, which are slightly different and much less accepted.
Rocmike aka American Patriot, not bad for you. You have only posted for over 2 hours under your new alias Michael MacGilvray, over 3 hours under Bill with some dfrogpong and anonymous posts thrown in there. All repeating the same crap over and over and going to old questions and answers. Either you are posting under new aliases I haven't found yet or maybe you are getting a life. I am betting you are posting under new aliases I haven't found yet.