A043530 Number of distinct base-3 digits of n.

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, 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, 3, 2, 2, 2, 3, 2, 3, 2, 2, 2, 2, 1, 2, 2, 3, 2, 2, 3, 3, 3, 3, 2

Offset

1,3

Comments

a(A031944(n)) = 3; a(A154314(n)) < 3. - Reinhard Zumkeller, Jan 07 2009

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

Links

Antti Karttunen, Table of n, a(n) for n = 1..19683

Mathematica

Table[Length[Union[IntegerDigits[n, 3]]], {n, 90}] (* Harvey P. Dale, May 13 2020 *)

Prog

(PARI) a(n) = #vecsort(digits(n, 3), , 8); \\ Michel Marcus, May 16 2016

Crossrefs

Cf. A007089, A031944, A037897, A154314.

Sequence in context: A103318 A197775 A002321 * A297771 A164995 A294108

Adjacent sequences: A043527 A043528 A043529 * A043531 A043532 A043533

Keyword

nonn,base

Author

Clark Kimberling

Status

approved