Hello Math-Fun, S = 2,5,26,159,1447,10274,45206,280278,2298281,... If we frame any comma above with its two closest digits we get 2.5 for the first comma, 5.2 for the second comma, 6.1 for the third one, etc. Look now: the division of 5 by 2 starts with 2.5 the division of 26 by 5 starts with 5.2 the division of 159 by 26 starts with 6.1 etc. [In other words, a(n+1)/a(n) starts with [x.y] with x = the rightmost digit of a(n) and y = the leftmost digit of a(n+1)]. As usual, we want S to be the lexico- graphically earliest seq of distinct terms with this property... but! Here comes the (Math-)fun part. I thought that S would increase monoto- nically for ever when I bumped into a(9) = 2298280 (and not, as above, = 2298281). I realized that S could decrease at some point! Indeed, this example works: 120,24,... as the result of 24/120 starts with 0.2). But this "zero comma" trick doesn't systematically work with integers ending in 0 (it works rarely, in reality). If it doesn't, we have to backtrack -- and increase by 1 the terms ending in "0" that would stop the sequence; this is what I did above. The question remains: will the "+1" trick always work? Or will S stop at some point? Enter into a loop? Extend for ever? [I've noticed that the ratio a(n+1)/a(n) gets closer at every stage to [x.y], (the divisor), but I don't know if it means something for the future of S]. Best, É. à+ É. Catapulté de mon aPhone