OFFSET
1,1
COMMENTS
The period per(w), for w = w[1..n] a word, is the least p >= 1 such that w[i] = w[i+p] for 1 <= i <= n-p.
Asymptotically we have a(n) ~ 1.732213...*2^n.
LINKS
D. Gabric and J. Shallit, Avoidance of split overlaps, arxiv preprint arXiv:2002.01968 [cs.DM], February 5 2020.
Rémy Sigrist, C program for A331699, Jan 26 2020.
EXAMPLE
For n = 3 there are two words of period 1 (000 and 111), two words of period 2 (010 and 101), and all other words are of period 3. So a(n) = 2*ceiling(3/1) + 2*ceiling(3/2) + 4*ceiling(3/3) = 14.
PROG
(C) See Links section.
CROSSREFS
KEYWORD
nonn
AUTHOR
Jeffrey Shallit, Jan 25 2020
EXTENSIONS
a(25)-a(33) from Rémy Sigrist, Jan 26 2020
STATUS
approved