A026606 [1->null]-transform of three-symbol Thue-Morse A026600, with 1 subtracted.

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

Offset: 1

Author

Clark Kimberling

Keywords

• nonn

Comments

Old name was: a(n) = b(n)-1, where b(n) = n-th term of A026600 that is not a 1.

From Michel Dekking, Apr 18 2019: (Start)

This sequence is a morphic sequence, i.e., a letter-to-letter projection of a fixed point of a morphism. Let the morphism sigma be given by

1->123, 2->456, 3->345,4->612, 5->561, 6->234,

and let the letter-to-letter map delta be given by

1->1, 2->2, 3->1, 4->2, 5->2, 6->1.

Then (a(n)) = delta(x), where x = 1234... is a fixed point of sigma.

This representation can be obtained by noting that this sequence, with 1 added, can also be viewed as the [1->23, 2->23, 3->32]-transform of A026600, and by doubling 1,2 and 3, renaming the resulting six letters as 1,2,3,4,5,6.

(End)

Crossrefs

Cf. A026605, A057215.

Extensions

Name changed by Michel Dekking, Apr 18 2019