login

Year-end appeal: Please make a donation to the OEIS Foundation to support ongoing development and maintenance of the OEIS. We are now in our 61st year, we have over 378,000 sequences, and we’ve reached 11,000 citations (which often say “discovered thanks to the OEIS”).

A107604
Order of appearance of twos in the Fibonacci substitution :triangular in form.
0
2, 2, 2, 2, 5, 2, 5, 2, 5, 7, 2, 5, 7, 2, 5, 7, 2, 5, 7, 10, 2, 5, 7, 10, 2, 5, 7, 10, 2, 5, 7, 10, 13, 2, 5, 7, 10, 13, 2, 5, 7, 10, 13, 15, 2, 5, 7, 10, 13, 15, 2, 5, 7, 10, 13, 15, 2, 5, 7, 10, 13, 15, 18, 2, 5, 7, 10, 13, 15, 18, 2, 5, 7, 10, 13, 15, 18, 20
OFFSET
0,1
COMMENTS
Fibonacci substitutions contain thrre types of informstion: 1) length 2) count of ones and twos 3) order of appearance of ones and twos
FORMULA
1->{1, 2}, 2->{1}
EXAMPLE
{}
2,
2,
2,
2,5,
2,5,
2,5,7,
2,5,7,
2,5,7,
2,5,7,10,
2,5,7,10,
2,5,7,10,
2,5,7,10,13
MATHEMATICA
s[1] = {1, 2}; s[2] = {1};; t[a_] := Flatten[s /@ a]; p[0] = {1}; p[1] = t[p[0]]; p[n_] := t[p[n - 1]] a = Table[Flatten[Table[If[p[i][[j]] == 2, j, {}], {j, 1, i}]], {i, 1, 20}]
CROSSREFS
Cf. A000045.
Sequence in context: A154097 A221491 A224254 * A080647 A324516 A181058
KEYWORD
nonn,uned,tabl
AUTHOR
Roger L. Bagula, Jun 09 2005
STATUS
approved