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%I #25 Apr 24 2021 21:28:34
%S 1,1,2,1,2,2,2,1,2,2,3,2,1,2,3,2,2,2,3,2,3,2,2,2,2,1,2,2,3,2,2,3,3,3,
%T 3,2,2,3,2,1,2,3,2,2,3,3,3,3,2,2,3,2,2,2,3,2,3,3,3,2,3,2,3,3,3,3,2,2,
%U 3,2,2,2,3,2,3,2,2,2,2,1,2,2,3,2,2,3,3,3,3,2
%N Number of distinct base-3 digits of n.
%C a(A031944(n)) = 3; a(A154314(n)) < 3. - _Reinhard Zumkeller_, Jan 07 2009
%C Image, under the coding sending i -> 1+floor(i/3), of the fixed point, starting with 0, of the morphism 0 -> 012, 1 -> 314, 2 -> 542, 3 -> 336, 4 -> 644, 5 -> 565, 6 -> 666. - _Jeffrey Shallit_, May 15 2016
%H Antti Karttunen, <a href="/A043530/b043530.txt">Table of n, a(n) for n = 1..19683</a>
%t Table[Length[Union[IntegerDigits[n,3]]],{n,90}] (* _Harvey P. Dale_, May 13 2020 *)
%o (PARI) a(n) = #vecsort(digits(n,3),,8); \\ _Michel Marcus_, May 16 2016
%Y Cf. A007089, A031944, A037897, A154314.
%K nonn,base
%O 1,3
%A _Clark Kimberling_
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