A121531 - cp's OEIS frontend

A121531 Triangle read by rows: T(n,k) is the number of nondecreasing Dyck paths of semilength n and having k double rises at an even level (n >= 1, k >= 0). A nondecreasing Dyck path is a Dyck path for which the sequence of the altitudes of the valleys is nondecreasing.

n	a(n)
1	1
2	2
3	4
4	1
5	7
6	6
7	12
8	20
9	2
10	20
11	51
12	18
13	33
14	115
15	80
16	5
17	54
18	240
19	262
20	54
21	88
22	477
23	725
24	294
25	13
26	143
27	916
28	1803
29	1158
30	161
31	232
32	1716
33	4170
34	3768
35	1026
36	34
37	376
38	3155
39	9152
40	10815
41	4684
42	475
43	609
44	5717
45	19311
46	28418
47	17432
48	3449
49	89
50	986
51	10240
52	39520

[1, 2, 4, 1, 7, 6, 12, 20, 2, 20, 51, 18, 33, 115, 80, 5, 54, 240, 262, 54, 88, 477, 725, 294, 13, 143, 916, 1803, 1158, 161, 232, 1716, 4170, 3768, 1026, 34, 376, 3155, 9152, 10815, 4684, 475, 609, 5717, 19311, 28418, 17432, 3449, 89, 986, 10240, 39520]

cp's OEIS Frontend

A121531 Triangle read by rows: T(n,k) is the number of nondecreasing Dyck paths of semilength n and having k double rises at an even level (n >= 1, k >= 0). A nondecreasing Dyck path is a Dyck path for which the sequence of the altitudes of the valleys is nondecreasing.

Table of values

List of values