Number of permutations of [n] having exactly ceiling(n/2)-1 alternating descents.
A302905
Number of permutations of [n] having exactly ceiling(n/2)-1 alternating descents.
Terms
- a(0) =1a(1) =1a(2) =1a(3) =2a(4) =7a(5) =36a(6) =182a(7) =1196a(8) =8699a(9) =76840a(10) =704834a(11) =7570716a(12) =84889638a(13) =1085246904a(14) =14322115212a(15) =211595659320
External references
- oeis: A302905