Number T(n,k) of permutations p of [n] with exactly k descents such that the up-down signature of p has nonnegative partial sums; triangle T(n,k), n>=0, 0<=k<=max(0,floor((n-1)/2)), read by rows.
A321280
Number T(n,k) of permutations p of [n] with exactly k descents such that the up-down signature of p has nonnegative partial sums; triangle T(n,k), n>=0, 0<=k<=max(0,floor((n-1)/2)), read by rows.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =2a(5) =1a(6) =8a(7) =1a(8) =22a(9) =22a(10) =1a(11) =52a(12) =172a(13) =1a(14) =114a(15) =856a(16) =604a(17) =1a(18) =240a(19) =3488a(20) =7296a(21) =1a(22) =494a(23) =12746a(24) =54746a(25) =31238a(26) =1a(27) =1004a(28) =43628a(29) =330068
External references
- oeis: A321280