A186367 - cp's OEIS frontend

A186367 Number of cycles in all cycle-up-down permutations of {1,2,...,n}. A permutation is said to be cycle-up-down if it is a product of up-down cycles. A cycle (b(1), b(2), ...) is said to be up-down if, when written with its smallest element in the first position, it satisfies b(1)b(3)<... .

n	a(n)
1	1
2	3
3	10
4	38
5	165
6	812
7	4478
8	27408
9	184529
10	1356256
11	10809786
12	92892928
13	856329253
14	8430600960
15	88292571934
16	980197173248
17	11499036105537
18	142147625652224
19	1846872283846922
20	25161923756064768
21	358706981125488581
22	5340498034862030848

[1, 3, 10, 38, 165, 812, 4478, 27408, 184529, 1356256, 10809786, 92892928, 856329253, 8430600960, 88292571934, 980197173248, 11499036105537, 142147625652224, 1846872283846922, 25161923756064768, 358706981125488581, 5340498034862030848]

cp's OEIS Frontend

A186367 Number of cycles in all cycle-up-down permutations of {1,2,...,n}. A permutation is said to be cycle-up-down if it is a product of up-down cycles. A cycle (b(1), b(2), ...) is said to be up-down if, when written with its smallest element in the first position, it satisfies b(1)b(3)<... .

Table of values

List of values