A107792 Threes order in the tribonacci substitution of three symbols.

3, 5, 8, 9, 12, 14, 17, 19, 22, 23, 26, 28, 31, 34, 36, 39, 40, 43, 45, 48, 49, 52, 54, 57, 60, 62, 65, 66, 69, 71, 74, 76, 79, 80, 83, 85, 88, 91, 93, 96, 97, 100, 102, 105, 107, 110, 111, 114, 116, 119, 122, 124, 127, 128, 131, 133, 136, 137, 140, 142, 145, 148, 150

Offset

0,1

Links

Table of n, a(n) for n=0..62.

Formula

1->(2), 2->{3}, 3->{1, 2, 3}, a(n) = order of appearance of threes in the substitution

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]] pp = p[12] a = Flatten[Table[If[pp[[j]] == 3, j, {}], {j, 1, Length[pp]}]]

Crossrefs

Cf. A000045, A000213.

Sequence in context: A325168 A211703 A274430 * A051206 A081451 A107605

Adjacent sequences: A107789 A107790 A107791 * A107793 A107794 A107795

Keyword

nonn,uned

Author

Roger L. Bagula, Jun 11 2005

Status

approved