A107641 Order of appearance of threes in the tribonacci ( Rauzy type) substitution: triangular.

1, 3, 2, 1, 4, 3, 5, 2, 5, 6, 1, 4, 6, 3, 5, 8, 9, 2, 5, 6, 9, 1, 4, 6, 9, 3, 5, 8, 9, 12, 2, 5, 6, 9, 11, 1, 4, 6, 9, 12, 14, 3, 5, 8, 9, 12, 14, 2, 5, 6, 9, 11, 14, 1, 4, 6, 9, 12, 14, 17, 3, 5, 8, 9, 12, 14, 17, 2, 5, 6, 9, 11, 14, 17, 19, 1, 4, 6, 9, 12, 14, 17, 18

Offset

0,2

Links

Table of n, a(n) for n=0..82.

Formula

1->{2}, 2->{3}, 3->{1, 2, 3}

Mathematica

s[1] = {2}; s[2] = {3};; s[3] = {1, 2, 3}; t[a_] := Flatten[s /@ a]; p[0] = {1}; p[1] = t[p[0]]; p[n_] := t[p[n - 1]] a = Table[Flatten[Table[If[(Length[p[i]]) >= j && (p[i][[j]] == 3), j, {}], {j, 1, i}]], {i, 1, 20}] MatrixForm[a] b = Flatten[a]

Crossrefs

Cf. A000073.

Sequence in context: A327467 A347832 A077427 * A299352 A127671 A271724

Adjacent sequences: A107638 A107639 A107640 * A107642 A107643 A107644

Keyword

nonn,uned

Author

Roger L. Bagula, Jun 09 2005

Status

approved