63247546domain: NAppears in sequencesStart to read the sequence digit by digit and erase the first "1" you encounter, then the first "2", the first "3", etc., until the first "9"; go on from there and erase again the first "1", the first "2", etc., until "9" -- and so on, cyclically until the end of the (infinite) sequence. Concatenate what is left. The result is the concatenation of all integers of the sequence.at n=21A108709