Lexicographically smallest permutation of the natural numbers such that in decimal representation the initial digit for each term is equal to the last non-zero digit of its predecessor; a(1)=1.
1, 10, 11, 12, 2, 20, 21, 13, 3, 30, 31, 14, 4, 40, 41, 15, 5, 50, 51, 16, 6, 60, 61, 17, 7
1 seqfan posts
Thu Dec 22 12:59:38 CET 2011 [seqfan] Re: Digit chain