A103957 A nonsense sequence.

1, 1, 2, 1, 1, 2, 1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 2, 1, 2, 1, 3, 1, 2, 1, 3, 1, 2, 1, 3, 1, 2, 1, 1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 2, 1, 2, 1, 3, 1, 2, 1, 3, 1, 2, 1, 3, 1, 2, 1, 1, 1, 2, 1, 2, 1, 2, 1, 3, 1, 2, 1, 2, 1, 3, 1, 2, 1, 3, 1, 2, 1, 3, 1, 2, 1, 1, 2, 1, 2, 1, 3, 1, 2, 1, 3, 1, 2

Offset: 0

Author

Roger L. Bagula, Mar 30 2005

Keywords

• nonn
• uned
• less

Crossrefs

Cf. A073058, A103684.

Programs

Mathematica

Hofstadter[n_Integer? Positive] := Hofstadter[n] = Hofstadter[n - Hofstadter[n - 1]] + Hofstadter[n - Hofstadter[n - 2]];
Hofstadter[0] = Hofstadter[1] = 1;
s[1] = {1, 2}; s[2] = {1, 3}; s[3] = {1};
t[a_] := Join[a, Flatten[s /@ a]];
p[0] = {1}; p[1] = t[{1}];
p[n_] := t[p[n - 1]];
Flatten[Table[p[If[n > 0, Hofstadter[n], n]], {n, 0, 7}]]

Formula

Involves substitutions 1-> {1, 2}, 2->{1, 3}, 3->1.