A278045 -id:A278045 - cp's OEIS frontend

A080843 Tribonacci word: limit S(infinity), where S(0) = 0, S(1) = 0,1, S(2) = 0,1,0,2 and for n >= 0, S(n+3) = S(n+2) S(n+1) S(n).

0, 1, 0, 2, 0, 1, 0, 0, 1, 0, 2, 0, 1, 0, 1, 0, 2, 0, 1, 0, 0, 1, 0, 2, 0, 1, 0, 2, 0, 1, 0, 0, 1, 0, 2, 0, 1, 0, 1, 0, 2, 0, 1, 0, 0, 1, 0, 2, 0, 1, 0, 0, 1, 0, 2, 0, 1, 0, 1, 0, 2, 0, 1, 0, 0, 1, 0, 2, 0, 1, 0, 2, 0, 1, 0, 0, 1, 0, 2, 0, 1, 0, 1, 0, 2, 0, 1, 0, 0, 1, 0, 2, 0, 1, 0, 1, 0, 2, 0, 1, 0, 0, 1, 0, 2

Offset: 0

N. J. A. Sloane, Mar 29 2003

An Arnoux-Rauzy or episturmian word.
From N. J. A. Sloane, Jul 10 2018: (Start)
The initial terms in a form suitable for copying:
0,1,0,2,0,1,0,0,1,0,2,0,1,0,1,0,2,0,1,0,0,1,0,2,0,1,0,2,0,1,0,0,1,0,2,0,1,
0,1,0,2,0,1,0,0,1,0,2,0,1,0,0,1,0,2,0,1,0,1,0,2,0,1,0,0,1,0,2,0,1,0,2,0,1,
0,0,1,0,2,0,1,0,1,0,2,0,1,0,0,1,0,2,0,1,0,1,0,2,0,1,0,0,1,0,2,0,1,0,2,0,1,
0,0,1,0,2,0,1,0,1,0,2,0,1,0,0,1,0,2,0,1,0,0,1,0,2,0,1,0,1,0,2,0,1,0,0,1,0,
2,0,1,0,2,0,1,0,0,1,0,2,0,1,0,1,0,2,0,1,0,0,1,0,2,0,1,0,2,0,1,0,0,1,0,2,0,
1,0,1,0,2,0,1,0,0,1,0,2,0,1,0,0,1,0,2,0,1,0,1,0,2,0,1,0,0,1,0,2,0,1,0,2,0,
1,0,0,1,0,2,0,1,0,1,0,2,0,1,0,0,1,0,2,0,1,0,1,0,2,0,1,0,0,1,0,2,0,1,0,2,0,
1,0,0,1,0,2,0,1,0,1,0,2,0,1,0,0,1,0,2,0,1,0,0,1,0,2,0,1,0,1,0,2,0,1,0,0,1,
...
Let TTW(a,b,c) denote this sequence written over the alphabet {a,b,c}. It begins:
a,b,a,c,a,b,a,a,b,a,c,a,b,a,b,a,c,a,b,a,a,b,a,c,a,b,a,c,a,b,a,a,b,a,c,a,b,
a,b,a,c,a,b,a,a,b,a,c,a,b,a,a,b,a,c,a,b,a,b,a,c,a,b,a,a,b,a,c,a,b,a,c,a,b,
a,a,b,a,c,a,b,a,b,a,c,a,b,a,a,b,a,c,a,b,a,b,a,c,a,b,a,a,b,a,c,a,b,a,c,a,b,
a,a,b,a,c,a,b,a,b,a,c,a,b,a,a,b,a,c,a,b,a,a,b,a,c,a,b,a,b,a,c,a,b,a,a,b,a,
c,a,b,a,c,a,b,a,a,b,a,c,a,b,a,b,a,c,a,b,a,a,b,a,c,a,b,a,c,a,b,a,a,b,a,c,a,
b,a,b,a,c,a,b,a,a,b,a,c,a,b,a,a,b,a,c,a,b,a,b,a,c,a,b,a,a,b,a,c,a,b,a,c,a,
b,a,a,b,a,c,a,b,a,b,a,c,a,b,a,a,b,a,c,a,b,a,b,a,c,a,b,a,a,b,a,c,a,b,a,c,a,
b,a,a,b,a,c,a,b,a,b,a,c,a,b,a,a,b,a,c,a,b,a,a,b,a,c,a,b,a,b,a,c,a,b,a,a,b,
... (End)
From Wolfdieter Lang, Aug 14 2018: (Start)
The substitution sequence 0 -> 0, 1; 1-> 0, 2; 2 -> 0  read as an irregular triangle with rows l >= 1 and length T(l+2), with the tribonacci numbers T = A000073, leads to the tribonacci tree TriT with level TriT(l) for l >= 1 given by a(0), a(1), ..., a(T(l+2)-1).
  E.g., l = 4:  0 1  0 2  0 1  0 with T(6) = 7 leaves (nodes). See the example below.
This tree can be used to find the tribonacci representation of nonnegative n given in A278038, call it ZTri(n) (Z for generalized Zeckendorf), by replacing every 2 by 1, and reading from bottom to top, omitting the final 0, except for n = 0 which is represented by 0. See the example below. (End)

			From _Joerg Arndt_, Mar 12 2013: (Start)
The first few steps of the substitution are
Start: 0
Rules:
  0 --> 01
  1 --> 02
  2 --> 0
-------------
0:   (#=1)
  0
1:   (#=2)
  01
2:   (#=4)
  0102
3:   (#=7)
  0102010
4:   (#=13)
  0102010010201
5:   (#=24)
  010201001020101020100102
6:   (#=44)
  01020100102010102010010201020100102010102010
7:   (#=81)
  010201001020101020100102010201001020101020100102010010201010201001020102010010201
(End)
From _Wolfdieter Lang_, Aug 14 2018: (Start)
The levels l of the tree TriT begin (the branches (edges) have been omitted):
Substitution rule: 0 -> 0 1; 1 -> 0 2; 2 -> 0.
l=1:                                 0
l=2:                  0                                 1
l=3:             0             1                  0             2
l=4:         0      1       0     2          0       1          0
l=5:      0    1  0   2   0   1   0        0   1   0   2      0    1
...
----------------------------------------------------------------------------------
n =       0    1  2   3   4   5   6        7   8   9  10     11   12
The tribonacci representation of n >= 0 (A278038; here at level 5 for n = 0.. 12) is obtained by reading from bottom to top (along the branches not shown) replacing 2 with 1, omitting the last 0 except for n = 0.
          0    1  0   1   0   1   0        0   1   0  1      0    1
                  1   1   0   0   1        0   0   1  1      0    0
                          1   1   1        0   0   0  0      1    1
                                           1   1   1  1      1    1
E.g., ZTri(9) = A278038(9) = 1010. (End)

The entry A092782 has a more complete list of references and links. - N. J. A. Sloane, Aug 17 2018
J.-P. Allouche and J. Shallit, Automatic Sequences, Cambridge Univ. Press, 2003, p. 246.

N. J. A. Sloane, Table of n, a(n) for n = 0..20000
Jean Berstel and J. Karhumaki, Combinatorics on words - a tutorial, Bull. EATCS, #79 (2003), pp. 178-228.
Nataliya Chekhova, Pascal Hubert, and Ali Messaoudi, Propriétés combinatoires, ergodiques et arithmétiques de la substitution de Tribonacci, Journal de théorie des nombres de Bordeaux, 13.2 (2001): 371-394.
D. Damanik and L. Q. Zamboni, Arnoux-Rauzy subshifts: linear recurrence, powers and palindromes, arXiv:math/0208137 [math.CO], 2002.
F. Michel Dekking, Morphisms, Symbolic Sequences, and Their Standard Forms, Journal of Integer Sequences, Vol. 19 (2016), Article 16.1.1.
F. Michel Dekking, Jeffrey Shallit, and N. J. A. Sloane, Queens in exile: non-attacking queens on infinite chess boards, Electronic J. Combin., 27:1 (2020), #P1.52.
Eric Duchêne and Michel Rigo, A morphic approach to combinatorial games: the Tribonacci case. RAIRO - Theoretical Informatics and Applications, 42, 2008, pp 375-393. doi:10.1051/ita:2007039. [Also available here]
Robbert Fokkink and Dan Rust, Queen reflections: a modification of Wythoff Nim, Int'l J. Game Theory (2022).
Wolfdieter Lang, The Tribonacci and ABC Representations of Numbers are Equivalent, arXiv:1810.09787v1 [math.NT], 2018.
Joseph Meleshko, Pascal Ochem, Jeffrey Shallit, and Sonja Linghui Shan, Pseudoperiodic Words and a Question of Shevelev, arXiv:2207.10171 [math.CO], 2022.
Aayush Rajasekaran, Narad Rampersad and Jeffrey Shallit, Overpals, Underlaps, and Underpals, In: Brlek S., Dolce F., Reutenauer C., Vandomme É. (eds) Combinatorics on Words, WORDS 2017, Lecture Notes in Computer Science, vol 10432.
Gérard Rauzy, Nombres algébriques et substitutions, Bull. Soc. Math. France 110.2 (1982): 147-178. See page 148.
Bo Tan and Zhi-Ying Wen, Some properties of the Tribonacci sequence, European Journal of Combinatorics, 28 (2007) 1703-1719.
O. Turek, Abelian Complexity Function of the Tribonacci Word, J. Int. Seq. 18 (2015) # 15.3.4
Index entries for sequences that are fixed points of mappings

Cf. A003849 (the Fibonacci word), A092782.
See A092782 for a version over the alphabet {1,2,3}.
See A278045 for another construction.
Cf. A000073, A278038.
First differences: A317950. Partial sums: A319198.

M:=17; S[1]:=`0`; S[2]:=`01`; S[3]:=`0102`;
for n from 4 to M do S[n]:=cat(S[n-1], S[n-2], S[n-3]); od:
t0:=S[M]: l:=length(t0); for i from 1 to l do lprint(i,substring(t0,i..i)); od:
# N. J. A. Sloane, Nov 01 2006
# A version that uses the letters a,b,c:
M:=10; B[1]:=`a`; B[2]:=`ab`; B[3]:=`abac`;
for n from 4 to M do B[n]:=cat(B[n-1], B[n-2], B[n-3]); od:
B[10]; # N. J. A. Sloane, Oct 30 2018

Nest[Flatten[ # /. {0 -> {0, 1}, 1 -> {0, 2}, 2 -> {0}}] &, {0}, 8] (* updated by Robert G. Wilson v, Nov 07 2010 *)
SubstitutionSystem[{0->{0,1},1->{0,2},2->{0}},{0},{8}]//Flatten (* Harvey P. Dale, Nov 21 2021 *)

strsub(s, vv, off=0)=
{
    my( nl=#vv, r=[], ct=1 );
    while ( ct <= #s,
        r = concat(r, vv[ s[ct] + (1-off) ] );
        ct += 1;
    );
    return( r );
}
t=[0];  for (k=1, 10, t=strsub( t, [[0,1], [0,2], [0]], 0 ) );  t
\\ Joerg Arndt, Sep 14 2013

Fixed point of morphism 0 -> 0, 1; 1 -> 0, 2; 2 -> 0.

a(n) = A092782(n+1) - 1. - Joerg Arndt, Sep 14 2013

More terms from Antonio G. Astudillo (afg_astudillo(AT)lycos.com), Apr 06 2003

A356749 a(n) is the number of trailing 1's in the dual Zeckendorf representation of n (A104326).

Original entry on oeis.org

0, 1, 0, 2, 1, 0, 3, 0, 2, 1, 0, 4, 1, 0, 3, 0, 2, 1, 0, 5, 0, 2, 1, 0, 4, 1, 0, 3, 0, 2, 1, 0, 6, 1, 0, 3, 0, 2, 1, 0, 5, 0, 2, 1, 0, 4, 1, 0, 3, 0, 2, 1, 0, 7, 0, 2, 1, 0, 4, 1, 0, 3, 0, 2, 1, 0, 6, 1, 0, 3, 0, 2, 1, 0, 5, 0, 2, 1, 0, 4, 1, 0, 3, 0, 2, 1, 0

Offset: 0

Amiram Eldar, Aug 25 2022

The asymptotic density of the occurrences of k = 0, 1, 2, ... is 1/phi^(k+2), where phi = 1.618033... (A001622) is the golden ratio.

The asymptotic mean of this sequence is phi.

			  n  a(n)  A104326(n)
  -  ----  ----------
  0     0           0
  1     1           1
  2     0          10
  3     2          11
  4     1         101
  5     0         110
  6     3         111
  7     0        1010
  8     2        1011
  9     1        1101

Amiram Eldar, Table of n, a(n) for n = 0..10000

Cf. A001622, A104326.

Similar sequences: A003849, A035614, A276084, A278045.

fb[n_] := Module[{k = Ceiling[Log[GoldenRatio, n*Sqrt[5]]], t = n, fr = {}}, While[k > 1, If[t >= Fibonacci[k], AppendTo[fr, 1]; t = t - Fibonacci[k], AppendTo[fr, 0]]; k--]; fr]; f[v_] := Module[{m = Length[v], k}, k = m; While[v[[k]] == 1, k--]; m - k]; a[n_] := Module[{v = fb[n]}, nv = Length[v]; i = 1; While[i <= nv - 2, If[v[[i ;; i + 2]] == {1, 0, 0}, v[[i ;; i + 2]] = {0, 1, 1}; If[i > 2, i -= 3]]; i++]; i = Position[v, _?(# > 0 &)]; If[i == {}, 0, f[v[[i[[1, 1]] ;; -1]]]]]; Array[a, 100, 0]

A308197 Numbers m such that the tribonacci representation of m (A278038) ends in an even number of 0's.

Original entry on oeis.org

1, 3, 4, 5, 8, 10, 11, 12, 13, 14, 16, 17, 18, 21, 23, 25, 27, 28, 29, 32, 34, 35, 36, 37, 38, 40, 41, 42, 44, 45, 47, 48, 49, 52, 54, 55, 56, 57, 58, 60, 61, 62, 65, 67, 69, 71, 72, 73, 76, 78, 79, 80, 82, 84, 85, 86, 89, 91, 92, 93, 94, 95, 97, 98, 99, 102, 104, 106, 108, 109, 110, 113, 115, 116, 117, 118, 119, 121

Offset: 1

N. J. A. Sloane, Jun 22 2019

The asymptotic density of this sequence is c/(c+1) = 0.647798..., where c = 1.839286... (A058265) is the tribonacci constant. - Amiram Eldar, Mar 04 2022

Amiram Eldar, Table of n, a(n) for n = 1..10000

Cf. A278038, A278045, A308198, A058265.

t[1] = 1; t[2] = 2; t[3] = 4; t[n_] := t[n] = t[n - 1] + t[n - 2] + t[n - 3]; q[n_] := Module[{s = {}, m = n, k}, While[m > 0, k = 1; While[t[k] <= m, k++]; k--; AppendTo[s, k]; m -= t[k]; k = 1]; EvenQ[Min[s] - 1]]; Select[Range[0, 121], q] (* Amiram Eldar, Mar 04 2022 *)

A308198 Numbers m such that the tribonacci representation of m (A278038) ends in an odd number of 0's.

Original entry on oeis.org

0, 2, 6, 7, 9, 15, 19, 20, 22, 24, 26, 30, 31, 33, 39, 43, 46, 50, 51, 53, 59, 63, 64, 66, 68, 70, 74, 75, 77, 81, 83, 87, 88, 90, 96, 100, 101, 103, 105, 107, 111, 112, 114, 120, 124, 127, 131, 132, 134, 140, 144, 145, 147, 151, 155, 156, 158, 164, 168, 169, 171, 173, 175, 179, 180, 182, 188, 192, 195, 199, 200, 202

Offset: 1

N. J. A. Sloane, Jun 22 2019

The asymptotic density of this sequence is 1/(c+1) = 0.352201..., where c = 1.839286... (A058265) is the tribonacci constant. - Amiram Eldar, Mar 04 2022

Amiram Eldar, Table of n, a(n) for n = 1..10000

Cf. A278038, A278045, A308197, A058265.

t[1] = 1; t[2] = 2; t[3] = 4; t[n_] := t[n] = t[n - 1] + t[n - 2] + t[n - 3]; q[0] = True; q[n_] := Module[{s = {}, m = n, k}, While[m > 0, k = 1; While[t[k] <= m, k++]; k--; AppendTo[s, k]; m -= t[k]; k = 1]; OddQ[Min[s] - 1]]; Select[Range[0, 202], q] (* Amiram Eldar, Mar 04 2022 *)

A356898 a(n) is the number of trailing 1's in the maximal tribonacci representation of n (A352103).

Original entry on oeis.org

0, 1, 0, 2, 0, 1, 0, 3, 1, 0, 2, 0, 1, 0, 4, 0, 2, 0, 1, 0, 3, 1, 0, 2, 0, 1, 0, 5, 0, 1, 0, 3, 1, 0, 2, 0, 1, 0, 4, 0, 2, 0, 1, 0, 3, 1, 0, 2, 0, 1, 0, 6, 1, 0, 2, 0, 1, 0, 4, 0, 2, 0, 1, 0, 3, 1, 0, 2, 0, 1, 0, 5, 0, 1, 0, 3, 1, 0, 2, 0, 1, 0, 4, 0, 2, 0, 1

Offset: 0

Amiram Eldar, Sep 03 2022

The asymptotic density of the occurrences of k = 0, 1, 2, ... is (c-1)/c^(k+1), where c = 1.839286... (A058265) is the tribonacci constant.

The asymptotic mean of this sequence is 1/(c-1) = 1.191487...

			  n  a(n)  A352103(n)
  -  ----  ----------
  0     0           0
  1     1           1
  2     0          10
  3     2          11
  4     0         100
  5     1         101
  6     0         110
  7     3         111
  8     1        1001
  9     0        1010

Amiram Eldar, Table of n, a(n) for n = 0..10000

Cf. A058265, A352103, A356896, A356897.

Similar sequences: A278045, A356749.

t[1] = 1; t[2] = 2; t[3] = 4; t[n_] := t[n] = t[n - 1] + t[n - 2] + t[n - 3]; trib[n_] := Module[{s = {}, m = n, k}, While[m > 0, k = 1; While[t[k] <= m, k++]; k--; AppendTo[s, k]; m -= t[k]; k = 1]; IntegerDigits[Total[2^(s - 1)], 2]]; f[v_] := Module[{m = Length[v], k}, k = m; While[v[[k]] == 1, k--]; m - k]; a[n_] := Module[{v = trib[n]}, nv = Length[v]; i = 1; While[i <= nv - 3, If[v[[i ;; i + 3]] == {1, 0, 0, 0}, v[[i ;; i + 3]] = {0, 1, 1, 1}; If[i > 3, i -= 4]]; i++]; i = Position[v, _?(# > 0 &)]; If[i == {}, 0, f[v[[i[[1, 1]] ;; -1]]], 10]]; Array[a, 100, 0]

A352427 a(n) is the number of trailing 0's in the minimal representation of n in terms of the positive Pell numbers (A317204).

Original entry on oeis.org

0, 1, 0, 1, 2, 0, 1, 0, 1, 2, 0, 3, 0, 1, 0, 1, 2, 0, 1, 0, 1, 2, 0, 3, 0, 1, 0, 1, 4, 0, 1, 0, 1, 2, 0, 1, 0, 1, 2, 0, 3, 0, 1, 0, 1, 2, 0, 1, 0, 1, 2, 0, 3, 0, 1, 0, 1, 4, 0, 1, 0, 1, 2, 0, 1, 0, 1, 2, 0, 5, 0, 1, 0, 1, 2, 0, 1, 0, 1, 2, 0, 3, 0, 1, 0, 1

Offset: 1

Amiram Eldar, Mar 16 2022

The asymptotic density of the occurrences of 0 is sqrt(2)-1 and of the occurrences of k = 1, 2, ... is 2*(sqrt(2)-1)^(k+1).

The asymptotic mean of this sequence is 1 and its asymptotic variance is sqrt(2).

Amiram Eldar, Table of n, a(n) for n = 1..10000

Cf. A000129, A003151, A003152, A286666, A286667, A317204.

Similar sequences: A003849 (dual Zeckendorf), A035614 (Zeckendorf), A230403 (factorial), A276084 (primorial), A278045 (tribonacci).

pell[1] = 1; pell[2] = 2; pell[n_] := pell[n] = 2*pell[n - 1] + pell[n - 2]; a[n_] := Module[{s = {}, m = n, k}, While[m > 0, k = 1; While[pell[k] <= m, k++]; k--; AppendTo[s, k]; m -= pell[k]; k = 1]; IntegerExponent[Total[3^(s - 1)], 3]]; Array[a, 100]

a(A000129(n)) = n-1 for n>=1.
a(n) = 0 if and only if n is in A286666.
a(n) > 0 if and only if n is in A286667.
a(n) == 0 (mod 2) if and only if n is in A003152.
a(n) == 1 (mod 2) if and only if n is in A003151.

cp's OEIS Frontend

A324473 k appears A278045(k)+1 times.

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A080843 Tribonacci word: limit S(infinity), where S(0) = 0, S(1) = 0,1, S(2) = 0,1,0,2 and for n >= 0, S(n+3) = S(n+2) S(n+1) S(n).

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A356749 a(n) is the number of trailing 1's in the dual Zeckendorf representation of n (A104326).

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A308197 Numbers m such that the tribonacci representation of m (A278038) ends in an even number of 0's.

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A308198 Numbers m such that the tribonacci representation of m (A278038) ends in an odd number of 0's.

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A356898 a(n) is the number of trailing 1's in the maximal tribonacci representation of n (A352103).

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A352427 a(n) is the number of trailing 0's in the minimal representation of n in terms of the positive Pell numbers (A317204).

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