Triangle read by rows: T(n,k) is the number of cycle-up-down permutations of {1,2,...,n} having k cycles (1<=k<=n).
A186366
Triangle read by rows: T(n,k) is the number of cycle-up-down permutations of {1,2,...,n} having k cycles (1<=k<=n).
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =3a(5) =1a(6) =2a(7) =7a(8) =6a(9) =1a(10) =5a(11) =20a(12) =25a(13) =10a(14) =1a(15) =16a(16) =70a(17) =105a(18) =65a(19) =15a(20) =1a(21) =61a(22) =287a(23) =490a(24) =385a(25) =140a(26) =21a(27) =1a(28) =272a(29) =1356
External references
- oeis: A186366