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A068861 a(1) = 1; a(n+1) is the smallest number not already in the sequence which differs from a(n) at every digit.

%I A068861 #11 Aug 30 2015 07:21:59
%S A068861 1,2,3,4,5,6,7,8,9,10,21,12,20,11,22,13,24,15,23,14,25,16,27,18,26,17,
%T A068861 28,19,30,29,31,40,32,41,33,42,34,43,35,44,36,45,37,46,38,47,39,48,50,
%U A068861 49,51,60,52,61,53,62,54,63,55,64,56,65,57,66,58,67,59,68,70,69,71,80
%N A068861 a(1) = 1; a(n+1) is the smallest number not already in the sequence which differs from a(n) at every digit.
%H A068861 Paul Tek, <a href="/A068861/b068861.txt">Table of n, a(n) for n = 1..10000</a>
%e A068861 11 follows 20 as the smallest number not included earlier and differing at every digit position.
%o A068861 (Haskell)
%o A068861 import Data.List (delete)
%o A068861 a068861 n = a068861_list !! (n-1)
%o A068861 a068861_list = f "x" (map show [1..]) where
%o A068861    f u us = g us where
%o A068861      g (v:vs)
%o A068861        | and $ zipWith (/=) u v = (read v :: Int) : f v (delete v us)
%o A068861        | otherwise = g vs
%o A068861 -- _Reinhard Zumkeller_, Dec 21 2013
%Y A068861 Cf. A068860, A068863.
%Y A068861 Cf. A067581.
%K A068861 nonn,base
%O A068861 1,2
%A A068861 _Amarnath Murthy_, Mar 13 2002