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Number of numbers <= n having as many distinct digits as n has.
1

%I #11 Jan 29 2014 07:52:14

%S 1,2,3,4,5,6,7,8,9,10,1,11,2,3,4,5,6,7,8,9,10,11,12,12,13,14,15,16,17,

%T 18,19,20,21,13,22,23,24,25,26,27,28,29,30,31,14,32,33,34,35,36,37,38,

%U 39,40,41,15,42,43,44,45,46,47,48,49,50,51,16,52,53

%N Number of numbers <= n having as many distinct digits as n has.

%H Reinhard Zumkeller, <a href="/A203814/b203814.txt">Table of n, a(n) for n = 0..10000</a>

%e a(9) = #{0, 1, 2, 3, 4, 5, 6, 7, 8, 9} = 10;

%e a(10) = #{10} = 1;

%e a(11) = #{0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 11} = 11;

%e a(12) = #{10, 12} = 2.

%o (Haskell)

%o a203814 n = length [x | x <- [0..n], a043537 x == a043537 n]

%Y Cf. A043537.

%K nonn,base,look

%O 0,2

%A _Reinhard Zumkeller_, Jan 06 2012