A334643 - cp's OEIS frontend

A334643 a(n) is the total number of down steps between the second and third 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	16
3	53
4	209
5	963
6	4816
7	25367
8	138531
9	777041
10	4449511
11	25901655
12	152818458
13	911755012
14	5491420104
15	33343242196
16	203881825163
17	1254342228285
18	7759025239189
19	48227078649155
20	301056318504165
21	1886647802277315
22	11864793375611820
23	74854437302309175

[0, 0, 16, 53, 209, 963, 4816, 25367, 138531, 777041, 4449511, 25901655, 152818458, 911755012, 5491420104, 33343242196, 203881825163, 1254342228285, 7759025239189, 48227078649155, 301056318504165, 1886647802277315, 11864793375611820, 74854437302309175]

cp's OEIS Frontend

A334643 a(n) is the total number of down steps between the second and third 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