%I #28 Jun 05 2017 16:48:24
%S 1,10,12,2,11,3,13,14,4,22,5,15,16,6,26,20,21,17,7,27,23,24,25,28,8,
%T 18,19,9,29,32,30,31,34,35,36,37,38,39,43,40,33,41,42,45,46,47,48,49,
%U 54,50,44,51,52,53,56,57,58,59,65,60,55,61,62,63,64,67,68
%N Starting with a(1) = 1, a(n) = smallest nonnegative integer not yet in the sequence such that the digits of a(n-1) and a(n) together are all distinct except for one digit that appears twice.
%e The terms a(5) = 11, a(6) = 3 are allowed since in both terms altogether the digit 1 appears twice. On the contrary, a(n-1) = 11, a(n) = 12 are not allowed since the digit 1 appears three times. Also a(n-1) = 11, a(n) = 22 are not allowed since two digits (not one) appear twice.
%t L = {1}; While[Length[L] < 100, k=2; While[ MemberQ[L, k] || (d = Plus @@ DigitCount[{k, L[[-1]]}]; ! SubsetQ[{0, 1, 2}, d] || Count[d, 2] != 1), k++]; AppendTo[L, k]]; L (* _Giovanni Resta_, May 22 2017 *)
%Y Cf. A287205.
%K nonn,fini,base
%O 1,2
%A _Enrique Navarrete_, May 15 2017
%E Data corrected by _Giovanni Resta_, May 22 2017