A357250 Number of quaternary steady words of length n (with respect to the permutations of symbols).

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

Martin Ehrenstein, Table of n, a(n) for n = 3..100

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

Adjacent sequences: A357247 A357248 A357249 * A357251 A357252 A357253

Keyword

nonn

Author

Michel Marcus, Sep 20 2022

Extensions

a(33)-a(51) from Martin Ehrenstein, Sep 22 2022

Status

approved