Triangle read by rows: T(n,k) is the number of odd permutations of {1,2,...,n} having k descents. (n>=1, k>=1).
A145883
Triangle read by rows: T(n,k) is the number of odd permutations of {1,2,...,n} having k descents. (n>=1, k>=1).
Terms
- a(0) =0a(1) =1a(2) =2a(3) =1a(4) =6a(5) =6a(6) =12a(7) =36a(8) =12a(9) =28a(10) =155a(11) =147a(12) =29a(13) =1a(14) =56a(15) =605a(16) =1208a(17) =586a(18) =64a(19) =1a(20) =120a(21) =2160a(22) =7800a(23) =7800a(24) =2160a(25) =120a(26) =240a(27) =7320a(28) =44160a(29) =78000
External references
- oeis: A145883