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Least nonnegative integer k such that the decimal representations of k and k+1 have n distinct digits in common.
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%I #2 Mar 30 2012 17:36:45

%S 0,10,100,1020,10230,102340,1023450,10234560,102345670,1023456780,

%T 10234567889

%N Least nonnegative integer k such that the decimal representations of k and k+1 have n distinct digits in common.

%C Finding a(10), the final term, could be a simple but instructive puzzle.

%C a(1) through a(9) is a subsequence of A121030. a(0) through a(9) is a subsequence of A107411.

%F For 1 <= n <= 10, a(n) is the least k such that A076489(k) = n. (This would be true for n = 0 also if A076489 considered nonnegative integers, having another initial 0 term and offset 0.).

%e a(10) = 10234567889 because 10234567889 and 10234567890 have all 10 decimal digits in common and this property does not hold for any smaller positive integer.

%Y Cf. A076489, A121030, A107411.

%K base,easy,fini,full,nonn

%O 0,2

%A _Rick L. Shepherd_, Aug 27 2009