1,2

The set of real numbers between 0 and 1 that contain no 1's in their ternary expansion is the well-known Cantor set with Hausdorff dimension log 2 / log 3.

Complement of A081606. - Reinhard Zumkeller (reinhard.zumkeller(AT)lhsystems.com), Mar 23 2003

Numbers n such that the n-th Apery number equals 1 (mod 3) (cf. A005258) - Benoit Cloitre (benoit7848c(AT)orange.fr), Nov 30 2003

Numbers n such that the n-th central Delannoy number equals 1 (mod 3) (cf. A001850) - Benoit Cloitre (benoit7848c(AT)orange.fr), Nov 30 2003

Numbers n such that there exists a permutation p_1, ..., p_n of 1, ..., n such that i + p_i is a power of 3 for every i - Ray Chandler (rayjchandler(AT)sbcglobal.net), Aug 3 2004

Subsequence of A125292; A125291(a(n)) = 1 for n>0. - Reinhard Zumkeller (reinhard.zumkeller(AT)lhsystems.com), Nov 26 2006

A062756(a(n)) = 0. - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Mar 02 2008

The first 2^n terms of the sequence could be obtained using the Cantor process for the segment [0,3^n-1]. E.g. for n=2 we have [0,{1},2,{3,4,5},6,{7},8]. The numbers outside of braces are the first 4 terms of the sequence. Therefore the terms of the sequence could be named as "Cantor's numbers". - Vladimir Shevelev (shevelev(AT)bgu.ac.il), Jun 13 2008

J.-P. Allouche and J. Shallit, The ring of k-regular sequences, Theoretical Computer Sci., 98 (1992), 163-197.

K. J. Falconer, The Geometry of Fractal Sets, Cambridge, 1985; p. 14.

M. Mendes France and A. J. van der Poorten, From geometry to Euler identities, Theoret. Comput. Sci., 65 (1989), 213-220.

T. D. Noe, Table of n, a(n) for n=1..1024

J.-P. Allouche and J. Shallit, The ring of k-regular sequences, Theoretical Computer Sci., 98 (1992), 163-197.

a(2n) = 3a(n), a(2n+1) = 3a(n)+2.

a(n) = Sum_{k = 1..n} 1 + 3^A007814(k) . - Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Jul 09 2005

If the offset were changed to zero, then: a(0)=0, a(n+1)=f(a(n)+1,f(a(n)+1) where f(x,y) = if x<3 and x<>1 then y else if x mod 3 = 1 then f(y+1,y+1) else f(floor(x/3),y). - Reinhard Zumkeller (reinhard.zumkeller(AT)gmail.com), Mar 02 2008

Select[ Range[ 0, 729 ], (Count[ IntegerDigits[ #, 3 ], 1 ]==0)& ]

Twice A005836. Cf. A032924, A014263, A007089, A062756, A061392, A005836, A001196, A097252-A097262.

Sequence in context: A066189 A137848 A053355 this_sequence A024431 A053658 A032393

Adjacent sequences: A005820 A005821 A005822 this_sequence A005824 A005825 A005826

nonn,easy,nice

njas, Jeffrey Shallit

More terms from Sascha Kurz (sascha.kurz(AT)uni-bayreuth.de), Mar 24 2002

Offset corrected by njas, Mar 02 2008. This may require some of the formulae to be adjusted.