OFFSET
0,2
COMMENTS
Asymptotically, a(n) ~ c*alpha^n, where alpha ~ 1.1127756842787054706297 is the largest positive real zero of X^7 - X - 1 and c ~ 20.665.
LINKS
Gabriele Fici and Luca Q. Zamboni, On the least number of palindromes contained in an infinite word, Theor. Comput. Sci. 481 (2013), 1-8.
Lukas Fleischer, Jeffrey Shallit, Words With Few Palindromes, Revisited, arxiv preprint arXiv:1911.12464 [cs.FL], November 27 2019.
FORMULA
a(n) = -a(n - 1) - a(n - 2) - a(n - 3) - a(n - 4) - a(n - 5) + 2a(n - 6) + 4a(n - 7) + 5a(n - 8) + 5a(n - 9) + 5a(n - 10) + 5a(n - 11) + 2a(n - 12) - 3a(n - 13) + -6a(n - 14) - 8a(n - 15) - 8a(n - 16) - 8a(n - 17) - 7a(n - 18) - 3a(n - 19) + 3a(n - 21) + 4a(n - 22) + 4a(n - 23) + 4a(n - 24) + 3a(n - 25) + 2a(n - 26) + a(n - 27) for n >= 42.
CROSSREFS
KEYWORD
nonn
AUTHOR
Jeffrey Shallit, Dec 02 2019
STATUS
approved