A214317 a(n) = length-n prefix of the Fibonacci word A003842.

1, 12, 121, 1211, 12112, 121121, 1211212, 12112121, 121121211, 1211212112, 12112121121, 121121211211, 1211212112112, 12112121121121, 121121211211212, 1211212112112121, 12112121121121211, 121121211211212112, 1211212112112121121, 12112121121121211212

Offset: 1

Author

N. J. A. Sloane, Jul 12 2012

Keywords

• nonn

Links

• Alois P. Heinz, Table of n, a(n) for n = 1..300

Crossrefs

Cf. A003842, A214318.

Programs

Maple

S:= proc(n) option remember;
      `if`(n<2, [2-n], [S(n-1)[], S(n-2)[]])
    end:
a:= proc(n) local k;
      for k while nops(S(k))Alois P. Heinz, Jul 19 2012

Mathematica

S = SubstitutionSystem[{1 -> {1, 2}, 2 -> {1}}, {1}, 20];
FromDigits[Take[#[[1]], #[[2]]]]& /@ Transpose[{S, Range[Length[S]]}] (* Jean-François Alcover, Nov 07 2020 *)