A191521 - cp's OEIS frontend

A191521 Triangle read by rows: T(n,k) is the number of left factors of Dyck paths of length n that have k valleys (i.e., a (1,-1)-step followed by a (1,1)-step).

n	a(n)
0	1
1	1
2	2
3	2
4	1
5	3
6	3
7	3
8	6
9	1
10	4
11	12
12	4
13	4
14	18
15	12
16	1
17	5
18	30
19	30
20	5
21	5
22	40
23	60
24	20
25	1
26	6
27	60
28	120
29	60
30	6
31	6
32	75
33	200
34	150
35	30
36	1
37	7
38	105
39	350
40	350
41	105
42	7
43	7
44	126
45	525
46	700
47	315
48	42
49	1
50	8
51	168
52	840
53	1400
54	840
55	168
56	8
57	8
58	196
59	1176
60	2450
61	1960
62	588
63	56
64	1
65	9
66	252
67	1764
68	4410
69	4410
70	1764
71	252
72	9

[1, 1, 2, 2, 1, 3, 3, 3, 6, 1, 4, 12, 4, 4, 18, 12, 1, 5, 30, 30, 5, 5, 40, 60, 20, 1, 6, 60, 120, 60, 6, 6, 75, 200, 150, 30, 1, 7, 105, 350, 350, 105, 7, 7, 126, 525, 700, 315, 42, 1, 8, 168, 840, 1400, 840, 168, 8, 8, 196, 1176, 2450, 1960, 588, 56, 1, 9, 252, 1764, 4410, 4410, 1764, 252, 9]

cp's OEIS Frontend

A191521 Triangle read by rows: T(n,k) is the number of left factors of Dyck paths of length n that have k valleys (i.e., a (1,-1)-step followed by a (1,1)-step).

Table of values

List of values