A118973 - cp's OEIS frontend

A118973 Number of hill-free Dyck paths of semilength n+2 and having length of first descent equal to 2 (a hill in a Dyck path is a peak at level 1).

n	a(n)
0	1
1	0
2	2
3	5
4	16
5	51
6	168
7	565
8	1934
9	6716
10	23604
11	83806
12	300154
13	1083137
14	3934404
15	14374413
16	52787766
17	194746632
18	721435884
19	2682522918
20	10008240456
21	37455101382
22	140569122624
23	528926230530
24	1994980278636
25	7541234323096

[1, 0, 2, 5, 16, 51, 168, 565, 1934, 6716, 23604, 83806, 300154, 1083137, 3934404, 14374413, 52787766, 194746632, 721435884, 2682522918, 10008240456, 37455101382, 140569122624, 528926230530, 1994980278636, 7541234323096]

cp's OEIS Frontend

A118973 Number of hill-free Dyck paths of semilength n+2 and having length of first descent equal to 2 (a hill in a Dyck path is a peak at level 1).

Table of values

List of values