A277921 Number of positive walks with n steps {-4,-3,-2,-1,0,1,2,3,4} starting at the origin, ending at altitude 2, and staying strictly above the x-axis.
0, 1, 4, 23, 142, 950, 6662, 48420, 361378, 2753687, 21334313, 167551836, 1330894754, 10673486660, 86306300366, 702872359332, 5759986152740, 47463395965108, 393027545388119, 3268814565684836, 27294209365111429, 228718165320327356, 1922825557218427271
Offset: 0
Links
- Alois P. Heinz, Table of n, a(n) for n = 0..1053
- 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.