login
A357250
Number of quaternary steady words of length n (with respect to the permutations of symbols).
1
1, 2, 3, 5, 5, 7, 9, 12, 16, 21, 28, 37, 45, 58, 73, 93, 101, 124, 150, 179, 216, 257, 309, 376, 453, 551, 662, 798, 957, 1149, 1371, 1647, 1977, 2382, 2871, 3450, 4160, 4995, 5991, 7190, 8631, 10370, 12462, 14991, 17983, 21608, 25947, 31157, 37406, 44921, 53921
OFFSET
3,2
COMMENTS
A squarefree word is steady if it remains squarefree after deletion of any single letter.
LINKS
Michał Dębski, Jarosław Grytczuk, and Bartłomiej Pawlik, Extensions and reductions of square-free words, arXiv:2209.08507 [math.CO], 2022. See Table 1 p. 3.
Michał Dębski, Jarosław Grytczuk, and Bartłomiej Pawlik, Extensions and reductions of squarefree words, Discrete Math. 347 (2024), 113825.
CROSSREFS
Sequence in context: A156899 A347737 A332286 * A156898 A084754 A120724
KEYWORD
nonn
AUTHOR
Michel Marcus, Sep 20 2022
EXTENSIONS
a(33)-a(51) from Martin Ehrenstein, Sep 22 2022
STATUS
approved