Number T(n,k) of permutations of [n] with exactly k ascents from odd to even numbers; triangle T(n,k), n>=0, 0<=k<=floor(n/2), read by rows.
A231777
Number T(n,k) of permutations of [n] with exactly k ascents from odd to even numbers; triangle T(n,k), n>=0, 0<=k<=floor(n/2), read by rows.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =1a(4) =4a(5) =2a(6) =8a(7) =14a(8) =2a(9) =54a(10) =60a(11) =6a(12) =162a(13) =402a(14) =150a(15) =6a(16) =1536a(17) =2712a(18) =768a(19) =24a(20) =6144a(21) =19704a(22) =12744a(23) =1704a(24) =24a(25) =75000a(26) =183120a(27) =94320a(28) =10320a(29) =120
External references
- oeis: A231777