A088569 Anti-Kolakoski sequence (sequence of run lengths never coincides with the sequence itself).

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

Offset

1,3

Comments

Unique infinite word defined on alphabet {1,2} satisfying: a(1)=1, if a(n)=2 length of n-th run is 1, if a(n)=1 length of n-th run is 2. Kolakoski sequence satisfies the opposite definition: K(1)=1, if K(n)=2 length of n-th run is 2, if K(n)=1 length of n-th run is 1.

Equals A049705 without the first term. - Jean-Christophe Hervé, Nov 10 2014

Links

Table of n, a(n) for n=1..105.

Formula

a(n) = 3 - A000002(n+1) = A049705(n+1).

Example

a(1)=1 hence first run must have length 2 and necessarily a(2)=1. Now second run must also have length 2 and therefore a(3) = a(4) = 2.

Crossrefs

Cf. A000002, A049705.

Sequence in context: A164295 A035214 A071292 * A246144 A192763 A001285

Adjacent sequences: A088566 A088567 A088568 * A088570 A088571 A088572

Keyword

nonn

Author

Benoit Cloitre, Nov 17 2003

Status

approved