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(2)>b(3)<... .
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(2)>b(3)<... .
Terms
- a(0) =1a(1) =3a(2) =10a(3) =38a(4) =165a(5) =812a(6) =4478a(7) =27408a(8) =184529a(9) =1356256a(10) =10809786a(11) =92892928a(12) =856329253a(13) =8430600960a(14) =88292571934a(15) =980197173248
External references
- oeis: A186367