A188512 Lengths of successive runs of identical terms in A188511.

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

Offset: 1

Author

N. J. A. Sloane, Apr 02 2011

Keywords

• nonn
• easy

Comments

A correspondent asked if this sequence was (apart from the initial terms) the same as the Fibonacci word A003842. It is not.

Period 7: repeat [2, 1, 2, 1, 2, 1, 1]. - Paolo Xausa, Jan 09 2025

Links

• Paolo Xausa, Table of n, a(n) for n = 1..10000
• Index entries for linear recurrences with constant coefficients, signature (0,0,0,0,0,0,1).

Crossrefs

Cf. A003842, A188511.

Programs

Mathematica

PadRight[{}, 100, {2, 1, 2, 1, 2, 1, 1}] (* Paolo Xausa, Jan 08 2025 *)

Formula

G.f.: (2 + x + 2*x^2 + x^3 + 2*x^4 + x^5 + x^6)/(1 - x^7). - Stefano Spezia, Jan 29 2025