I thought this may be an interesting topic. Starting with 2016 and working back which year is the first one not represented in your collection by a coin from somewhere in the world. I say 2016 and not 2017 because a lot of current years coins are still to be minted but 2016 in complete. I'll start the ball rolling, although I have no expectation that I will continue to have the long stretch for very long. The first year missing for me is 1858 - a run of 158 successive years. I am sure some of the oldtimers can go back way further.
That one's easy, see post #17 in this thread - https://www.cointalk.com/threads/wh...ost-attractive-circulating-gold-coins.291363/ edit - apologies, I misread your post the first go round. What I get for reading too fast. I no longer even collect coins.
Based on what other people have read I expected you to win this threads hands down with a sequence 2557 years!
Wellllllllll - if we were to count the coinage of Asia we could actually go back a good bit further than that. But who's counting ?
I dont have anything in the 20th-21st centuries, but my collection is a year / assayer / variety run from 1790 to 1821.