
LINKS

Table of n, a(n) for n=1..23.
Sergey V. Avgustinovich, Sergey Kitaev, Artem V. Pyatkin, and Alexandr Valyuzhenich, On SquareFree Permutations, Journal of Automata, Languages and Combinatorics 16(1): 310 (2011).
Ian Gent, Sergey Kitaev, Alexander Konovalov, Steve Linton and Peter Nightingale, Scrucial and bicrucial permutations with respect to squares, arXiv:1402.3582 [math.CO], 2014; and J. Int. Seq. 18 (2015) 15.6.5.
Carla Groenland and Tom Johnston, The lengths for which bicrucial squarefree permutations exist, arXiv:2109.00502 [math.CO], 2021.


EXAMPLE

a(7) = 60 since all rightcrucial permutations with respect to squares of length 7 are 2136547, 2137546, 2146537, 2147536, 2156437, 2157436, 2167435, 3146527, 3147526, 3156427, 3157426, 3167425, 3246517, 3247516, 3256417, 3257416, 3267415, 3421675, 3521674, 3621574, 3721564, 4156327, 4157326, 4167325, 4256317, 4257316, 4267315, 4356217, 4357216, 4367215, 4521673, 4531672, 4532671, 4621573, 4631572, 4632571, 4721563, 4731562, 4732561, 5167324, 5267314, 5367214, 5467213, 5621473, 5631472, 5632471, 5641372, 5642371, 5721463, 5731462, 5732461, 5741362, 5742361, 6721453, 6731452, 6732451, 6741352, 6742351, 6751342, 6752341.
