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%I #16 Mar 20 2024 09:22:42
%S 1,2,3,4,5,6,7,8,9,10,21,30,41,50,61,70,81,90,101,210,301,410,501,610,
%T 701,810,901,1010,2101,3010,4101,5010,6101,7010,8101,9010,10101,21010,
%U 30101,41010,50101,61010,70101,81010,90101,101010,210101,301010,410101,501010
%N a(1) = 1; a(n+1) is the smallest number > a(n) which differs from it at every digit.
%C a(9001) has 1001 digits. - _Michael S. Branicky_, Mar 19 2024
%H Michael S. Branicky, <a href="/A068860/b068860.txt">Table of n, a(n) for n = 1..9000</a>
%F a(n) = fabab... where f = ((n-1) mod 9) + 1 and ab = 01 if f is odd else 10 and has floor((n-1)/9)+1 digits. - _Michael S. Branicky_, Mar 19 2024
%e After 90 the next member is 101 which differs at each digit position.
%o (Python)
%o def a(n):
%o q, r = divmod(n-1, 9)
%o d, f = q+1, r+1
%o return int((str(f) + "0"*(f%2) + "10"*(d//2))[:d])
%o print([a(n) for n in range(1, 51)]) # _Michael S. Branicky_, Mar 19 2024
%Y Cf. A068861.
%K nonn,base
%O 1,2
%A _Amarnath Murthy_, Mar 13 2002
%E a(48) and beyond from _Michael S. Branicky_, Mar 19 2024
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