Triangle read by rows: T(n,k) is the number of permutations of {1,2,...,n} having k up-down cycles (0<=k<=n). 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)<... .
A186358
Triangle read by rows: T(n,k) is the number of permutations of {1,2,...,n} having k up-down cycles (0<=k<=n). 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) =0a(2) =1a(3) =0a(4) =1a(5) =1a(6) =1a(7) =1a(8) =3a(9) =1a(10) =4a(11) =6a(12) =7a(13) =6a(14) =1a(15) =19a(16) =35a(17) =30a(18) =25a(19) =10a(20) =1a(21) =114a(22) =210a(23) =190a(24) =125a(25) =65a(26) =15a(27) =1a(28) =799a(29) =1468
External references
- oeis: A186358