Number of permutations p() of 1..n+5 with centered difference p(i+1)-p(i-1) < 0 exactly 4 times.

A180882

Number of permutations p() of 1..n+5 with centered difference p(i+1)-p(i-1) < 0 exactly 4 times.

Terms

    a(0) =20a(1) =525a(2) =10010a(3) =130914a(4) =1438920a(5) =13547688a(6) =116189304a(7) =917857512a(8) =6866412696a(9) =48911180175a(10) =336896355510

External references