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Number of numbers <= n having distinct digits in their decimal representation, cf. A010784.
4

%I #10 Dec 15 2016 08:51:15

%S 1,2,3,4,5,6,7,8,9,10,11,11,12,13,14,15,16,17,18,19,20,21,21,22,23,24,

%T 25,26,27,28,29,30,31,31,32,33,34,35,36,37,38,39,40,41,41,42,43,44,45,

%U 46,47,48,49,50,51,51,52,53,54,55,56,57,58,59,60,61,61,62,63,64,65,66

%N Number of numbers <= n having distinct digits in their decimal representation, cf. A010784.

%C a(m)<=a(n) for m<n and a(n)=8877690 for n>=9876543210;

%C a(A010784(n)) = n; a(A109303(n)) = a(A109303(n)-1);

%C partial sums of A178788.

%H R. Zumkeller, <a href="/A178787/b178787.txt">Table of n, a(n) for n = 0..25000</a>

%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/Digit.html">Digit</a>

%e a(12) = #{0,1,2,3,4,5,6,7,8,9,10,12} = 12;

%e a(24) = a(12) + #{13,14,15,16,17,18,19,20,21,23,24} = 23.

%t f[n_] := Length[ Select[ Range[0, n], Max[ DigitCount[#]] == 1 &]]; Array[f, 70, 0] (* _Robert G. Wilson v_, Dec 13 2016 after _Harvey P. Dale_ in A010784 *)

%o (Haskell)

%o a178787 n = a178787_list !! n

%o a178787_list = scanl1 (+) a178788_list

%o -- _Reinhard Zumkeller_, Mar 15 2014

%K base,nonn

%O 0,2

%A _Reinhard Zumkeller_, Jun 30 2010