A334644 - cp's OEIS frontend

A334644 a(n) is the total number of down steps between the third and fourth up steps in all 2_1-Dyck paths of length 3*n. A 2_1-Dyck path is a lattice path with steps (1, 2), (1, -1) that starts and ends at y = 0 and stays above the line y = -1.

n	a(n)
0	0
1	0
2	0
3	83
4	299
5	1263
6	6076
7	31307
8	168561
9	936161
10	5321611
11	30804795
12	180939408
13	1075636912
14	6459103704
15	39120216196
16	238692219923
17	1465783144605
18	9052278085129
19	56185368932615
20	350293215459915
21	2192731008315015
22	13775745283576920
23	86831135890324875

[0, 0, 0, 83, 299, 1263, 6076, 31307, 168561, 936161, 5321611, 30804795, 180939408, 1075636912, 6459103704, 39120216196, 238692219923, 1465783144605, 9052278085129, 56185368932615, 350293215459915, 2192731008315015, 13775745283576920, 86831135890324875]

cp's OEIS Frontend

A334644 a(n) is the total number of down steps between the third and fourth up steps in all 2_1-Dyck paths of length 3*n. A 2_1-Dyck path is a lattice path with steps (1, 2), (1, -1) that starts and ends at y = 0 and stays above the line y = -1.

Table of values

List of values