Number of permutations of [n] beginning with at least ceiling(n/2) ascents.

A262034

Number of permutations of [n] beginning with at least ceiling(n/2) ascents.

Terms

    a(0) =1a(1) =0a(2) =1a(3) =1a(4) =4a(5) =5a(6) =30a(7) =42a(8) =336a(9) =504a(10) =5040a(11) =7920a(12) =95040a(13) =154440a(14) =2162160a(15) =3603600a(16) =57657600a(17) =98017920a(18) =1764322560a(19) =3047466240a(20) =60949324800a(21) =106661318400

External references