A264119 Look and say for Fibonacci word A003842.

1, 1, 1, 2, 2, 1, 1, 2, 1, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 1, 1, 1, 2, 2, 1, 1, 2, 1, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 1, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 1, 1, 1, 2, 2, 1, 1, 2, 1, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 1, 1, 1, 2, 2, 1, 1, 2, 1, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 1, 1, 1, 2, 2, 1, 1, 2, 2, 1, 1, 2, 1

Offset

0,4

Comments

Define strings S(0)=2, S(1)=1, S(n)=S(n-1)S(n-2); iterate.

A003842 is S(infinity) and begins 1, 2, 1, 1, 2, 1, 2.

We see one 1, one 2, two 1, one 2, one 1, one 2.

So this sequences begins 1,1, 1,2, 2,1, 1,2, 1,1, 1,2.

Links

Table of n, a(n) for n=0..104.

Patrice Séébold, Look and Say Fibonacci, RAIRO-Theor. Inf. Appl. 42 (2008) 729-746.

Prog

(PARI) lns(v) = {vls = []; nb = 0; old = -1; for (k=1, #v, if (v[k] == old, nb++, if (old != -1, vls = concat(vls, nb); vls = concat(vls, old); ); nb = 1; ); old = v[k]; ); vls = concat(vls, nb); vls = concat(vls, old); vls; }
lista(nn=11) = {v = [2]; w = [1]; for (k=1, nn, nw = concat(w, v); v = w; w = nw; ); lns(w); }

Crossrefs

Cf. A003842.

Sequence in context: A241418 A330348 A117229 * A225518 A269972 A202205

Adjacent sequences: A264116 A264117 A264118 * A264120 A264121 A264122

Keyword

nonn

Author

Michel Marcus, Apr 03 2016

Status

approved