A267311 Number of factors of length 2n of the Thue-Morse sequence (A010060) that are abelian squares.

2, 4, 4, 10, 8, 24, 10, 22, 12, 36, 20, 52, 24, 54, 20, 46, 24, 72, 32, 76, 32, 80, 40, 108, 42, 94, 42, 110, 50, 122, 42, 94, 44, 132, 60, 148, 60, 140, 60, 156, 68, 172, 68, 164, 68, 180, 84, 220, 88, 198, 76, 190, 80, 218, 92, 222, 88, 210, 92, 246, 104, 246, 84, 190, 88, 264, 112, 268, 104, 248

Offset

1,1

Comments

A "factor" is a contiguous block. An "abelian square" is a word of the form x x' where x' is a permutation of x.

Links

Table of n, a(n) for n=1..70.

Gabriele Fici, Filippo Mignosi, Jeffrey Shallit, Abelian-Square-Rich Words, arXiv:1701.00948 [cs.DM], 2016. See Table 1 p. 6.

Example

For n = 3 the three factors of length 6 are 001100, 101101, 010010, 110011.

Crossrefs

Cf. A010060.

Sequence in context: A363641 A247570 A054764 * A118336 A193852 A327544

Adjacent sequences: A267308 A267309 A267310 * A267312 A267313 A267314

Keyword

nonn

Author

Jeffrey Shallit, Jan 12 2016

Status

approved