a(1) = 1, a(n) = smallest positive number b not among a(1)..a(n-1) such that the last digit of b = the first digit of a(n-1).
1, 11, 21, 12, 31, 13, 41, 14, 51, 15, 61, 16, 71, 17, 81, 18, 91, 19, 101, 111, 121, 131
3 seqfan posts
Thu Jan 29 12:57:05 CET 2009 [seqfan] Re: Starting and Ending Digits