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A060898 Number of walks of length n on square lattice, starting at origin, staying in first, second and third quadrants. 6

%I

%S 1,4,14,54,200,776,2940,11466,43980,172170,665544,2612764,10154144,

%T 39949000,155864280,614260062,2403739140,9486263092,37209147800,

%U 147012850512,577741491404,2284848892872,8993216244896,35595538140656,140288753584200,555662416386840

%N Number of walks of length n on square lattice, starting at origin, staying in first, second and third quadrants.

%C Is there a formula analogous to the (conjectured) formula for A060900?

%H Alois P. Heinz, <a href="/A060898/b060898.txt">Table of n, a(n) for n = 0..1000</a>

%H M. Bousquet-Mélou, <a href="http://arxiv.org/abs/1511.02111">Plane lattice walks avoiding a quadrant</a>, arXiv:1511.02111 [math.CO], 2015.

%H Mireille Bousquet-Mélou, <a href="https://doi.org/10.1016/j.jcta.2016.06.010">Square lattice walks avoiding a quadrant</a>, Journal of Combinatorial Theory, Series A, Elsevier, 2016, Special issue for the 50th anniversary of the journal, 144, pp. 37-79. Also <hal-01225710v3>. See App. A.

%H Kilian Raschel, Amélie Trotignon, <a href="https://arxiv.org/abs/1807.08610">On walks avoiding a quadrant</a>, arXiv:1807.08610 [math.CO], 2018.

%Y Cf. A005566, A001700, A060897, A060899, A060900.

%K nonn,easy,walk

%O 0,2

%A _David W. Wilson_, May 05 2001

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Last modified January 27 12:00 EST 2020. Contains 331295 sequences. (Running on oeis4.)