A277923 - OEIS

A277923

Number of positive walks with n steps {-4,-3,-2,-1,1,2,3,4} starting at the origin, ending at altitude 2, and staying strictly above the x-axis.

%I #7 Nov 12 2016 17:47:28

%S 0,1,3,16,84,505,3121,20180,133604,904512,6224305,43432093,306524670,

%T 2184389874,15695947669,113595885023,827299204132,6058526521135,

%U 44586954104578,329579179316696,2445858862779018,18216235711289695,136113075865844577,1020074492384232296

%N Number of positive walks with n steps {-4,-3,-2,-1,1,2,3,4} starting at the origin, ending at altitude 2, and staying strictly above the x-axis.

%H Alois P. Heinz, <a href="/A277923/b277923.txt">Table of n, a(n) for n = 0..1113</a>

%H C. Banderier, C. Krattenthaler, A. Krinik, D. Kruchinin, V. Kruchinin, D. Nguyen, and M. Wallner, <a href="https://arxiv.org/abs/1609.06473">Explicit formulas for enumeration of lattice paths: basketball and the kernel method</a>, arXiv:1609.06473 [math.CO], 2016.

%Y Cf. A276901, A276852, A276902, A276903, A276904.`

%K nonn,walk

%O 0,3

%A _David Nguyen_, Nov 04 2016