

A107640


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


0



1, 2, 1, 4, 3, 5, 2, 4, 1, 4, 3, 5, 8, 2, 4, 7, 1, 4, 8, 10, 3, 5, 8, 11, 2, 4, 7, 11, 1, 4, 8, 10, 13, 3, 5, 8, 11, 13, 2, 4, 7, 11, 13, 1, 4, 8, 10, 13, 16, 3, 5, 8, 11, 13, 16, 2, 4, 7, 11, 13, 16, 18, 1, 4, 8, 10, 13, 16, 18, 3, 5, 8, 11, 13, 16, 20
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OFFSET

0,2


LINKS

Table of n, a(n) for n=0..75.


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]] == 2), j, {}], {j, 1, i}]], {i, 1, 20}] MatrixForm[a] b = Flatten[a]


CROSSREFS

Cf. A000073.
Sequence in context: A144334 A141210 A244373 * A030065 A328676 A269595
Adjacent sequences: A107637 A107638 A107639 * A107641 A107642 A107643


KEYWORD

nonn,uned,tabl


AUTHOR

Roger L. Bagula, Jun 09 2005


STATUS

approved



