A105641 - cp's OEIS frontend

A105641 Number of hill-free Dyck paths of semilength n, having no UUDD's, where U=(1,1) and D=(1,-1) (a hill in a Dyck path is a peak at level 1).

n	a(n)
2	0
3	1
4	2
5	5
6	14
7	39
8	111
9	322
10	947
11	2818
12	8470
13	25677
14	78420
15	241061
16	745265
17	2315794
18	7228702
19	22656505
20	71273364
21	224965675
22	712249471
23	2261326010
24	7197988973
25	22966210236
26	73437955105
27	235307698544
28	755395560220
29	2429293941019

[0, 1, 2, 5, 14, 39, 111, 322, 947, 2818, 8470, 25677, 78420, 241061, 745265, 2315794, 7228702, 22656505, 71273364, 224965675, 712249471, 2261326010, 7197988973, 22966210236, 73437955105, 235307698544, 755395560220, 2429293941019]

cp's OEIS Frontend

A105641 Number of hill-free Dyck paths of semilength n, having no UUDD's, where U=(1,1) and D=(1,-1) (a hill in a Dyck path is a peak at level 1).

Table of values

List of values