%I #35 Jan 23 2025 21:58:20
%S 2,4,12,48,280,1864,14840,132276,1323504
%N Number of non-overlapping permutations of length n. A permutation is non-overlapping (sometimes called minimally overlapping) if the shortest permutation containing two occurrences of it as a consecutive pattern has length 2n-1.
%H Miklós Bóna, <a href="https://people.clas.ufl.edu/bona/files/newno.pdf">Non-overlapping permutation patterns</a>, PU. M. A. 22(2):99-105, 2011.
%H Sergi Elizalde and Peter R. W. McNamara, <a href="http://arxiv.org/abs/1508.05963">The structure of the consecutive pattern poset</a>, arXiv:1508.05963 [math.CO], 2015. See p. 21.
%H Sergey Kirgizov and Khaydar Nurligareev, <a href="https://doi.org/10.1016/j.disc.2025.114400">Asymptotics of self-overlapping permutations</a>, Discrete Mathematics 348, 11440, (2025); <a href="https://arxiv.org/abs/2311.11677">Preprint</a> arXiv:2311.11677 [math.CO], 2023. See p. 2.
%H Ran Pan and Jeffrey B. Remmel, <a href="http://arxiv.org/abs/1510.08190">Minimal overlapping patterns for generalized Euler permutations, standard tableaux of rectangular shape, and column strict arrays</a>, arXiv:1510.08190 [math.CO], 2015.
%F For n>=3, a(n) is divisible by 4 (shown in the Elizalde/McNamara link).
%F The limit of a(n)/n! is approximately 0.364 (shown by M. Bóna).
%F An implicit formula of a(n) is given in Section 3 of Pan and Remmel's paper.
%e There are 4 non-overlapping permutations of length 3, namely 132, 213, 231 and 312.
%K nonn,more
%O 2,1
%A _Sergi Elizalde_, Oct 28 2015