A334977 - cp's OEIS frontend

A334977 a(n) is the total number of down steps between the (n-1)-th and n-th 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	1
2	9
3	53
4	299
5	1692
6	9690
7	56221
8	330165
9	1959945
10	11745435
11	70974252
12	432019844
13	2646716264
14	16307880462
15	100996570221
16	628356589721
17	3925544432355
18	24616047166095
19	154886752443885
20	977595783524955
21	6187863825170160
22	39269844955755960
23	249819662230403148

[0, 1, 9, 53, 299, 1692, 9690, 56221, 330165, 1959945, 11745435, 70974252, 432019844, 2646716264, 16307880462, 100996570221, 628356589721, 3925544432355, 24616047166095, 154886752443885, 977595783524955, 6187863825170160, 39269844955755960, 249819662230403148]

cp's OEIS Frontend

A334977 a(n) is the total number of down steps between the (n-1)-th and n-th 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