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.

0, 1, 3, 16, 84, 505, 3121, 20180, 133604, 904512, 6224305, 43432093, 306524670, 2184389874, 15695947669, 113595885023, 827299204132, 6058526521135, 44586954104578, 329579179316696, 2445858862779018, 18216235711289695, 136113075865844577, 1020074492384232296

Offset

0,3

Links

Alois P. Heinz, Table of n, a(n) for n = 0..1113

C. Banderier, C. Krattenthaler, A. Krinik, D. Kruchinin, V. Kruchinin, D. Nguyen, and M. Wallner, Explicit formulas for enumeration of lattice paths: basketball and the kernel method, arXiv:1609.06473 [math.CO], 2016.

Crossrefs

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

Sequence in context: A025187 A373277 A151328 * A076279 A056369 A056360

Adjacent sequences: A277920 A277921 A277922 * A277924 A277925 A277926

Keyword

nonn,walk

Author

David Nguyen, Nov 04 2016

Status

approved