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%I #21 Feb 13 2013 04:38:41
%S 1,1,1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,0,
%T 1,1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,0,1,
%U 1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,0,1,1,1,1,1,1,1,1,1,1,0,0,0,1,1,1
%N Characteristic function of numbers having distinct digits in their decimal representation.
%C a(A010784(n)) = 1; a(A109303(n)) = 0;
%C first differences of A178787.
%C a(n) <= A196368(n).
%C a(n) = 0 for n > 9*9!. - _Hieronymus Fischer_, Feb 02 2013
%H R. Zumkeller, <a href="/A178788/b178788.txt">Table of n, a(n) for n = 0..10000</a>
%H Eric Weisstein's World of Mathematics, <a href="http://mathworld.wolfram.com/Digit.html">Digit</a>
%H <a href="/index/Ch#char_fns">Index entries for characteristic functions</a>
%F a(n) = 0^(A055642(n)-A043537(n)).
%t lst = {}; Do[If[Select[Tally[IntegerDigits[n]][[All, 2]], # > 1 &] == {}, AppendTo[lst, 1], AppendTo[lst, 0]], {n, 0, 104}]; lst (* _Arkadiusz Wesolowski_, May 10 2012 *)
%o (Haskell)
%o import Data.List (nub)
%o a178788 n = fromEnum $ nub (show n) == show n
%o -- _Reinhard Zumkeller_, Sep 25 2011
%K base,nonn
%O 0,1
%A _Reinhard Zumkeller_, Jun 30 2010
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