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

A262033

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

Terms

    a(0) =1a(1) =1a(2) =1a(3) =3a(4) =4a(5) =20a(6) =30a(7) =210a(8) =336a(9) =3024a(10) =5040a(11) =55440a(12) =95040a(13) =1235520a(14) =2162160a(15) =32432400a(16) =57657600a(17) =980179200a(18) =1764322560a(19) =33522128640a(20) =60949324800

External references