A166294 - cp's OEIS frontend

A166294 Number of peaks at even level in all Dyck paths of semilength n with no UUU's and no DDD's, (U=(1,1), D=(1,-1)). These Dyck paths are counted by the secondary structure numbers (A004148).

n	a(n)
1	0
2	1
3	4
4	12
5	34
6	92
7	242
8	628
9	1616
10	4138
11	10570
12	26970
13	68798
14	175545
15	448176
16	1145058
17	2927924
18	7493021
19	19191836
20	49195806
21	126205062
22	324000494
23	832371414
24	2139802870
25	5504256592
26	14166936063
27	36483006046
28	94000206216

[0, 1, 4, 12, 34, 92, 242, 628, 1616, 4138, 10570, 26970, 68798, 175545, 448176, 1145058, 2927924, 7493021, 19191836, 49195806, 126205062, 324000494, 832371414, 2139802870, 5504256592, 14166936063, 36483006046, 94000206216]

cp's OEIS Frontend

A166294 Number of peaks at even level in all Dyck paths of semilength n with no UUU's and no DDD's, (U=(1,1), D=(1,-1)). These Dyck paths are counted by the secondary structure numbers (A004148).

Table of values

List of values